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数学汇总学术速递[1.10]

格林先生MrGreen arXiv每日学术速递 2022-05-05

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math数学汇总,共计102篇


【1】 QN Optimization with Hessian Sample
标题:基于黑森样本的QN优化

链接:https://arxiv.org/abs/2201.02608
作者:Joy Azzam,Daniel Henderson,Benjamin Ong,Allan Struthers
摘要:This article explores how to effectively incorporate curvature information generated using SIMD-parallel forward-mode Algorithmic Differentiation (AD) into unconstrained Quasi-Newton (QN) minimization of a smooth objective function, $f$. Specifically, forward-mode AD can be used to generate block Hessian samples $Y=\nabla^2 f(x)\,S$ whenever the gradient is evaluated. Block QN algorithms then update approximate inverse Hessians, $H_k \approx \nabla^2 f(x_k)$, with these Hessian samples. Whereas standard line-search based BFGS algorithms carefully filter and correct secant-based approximate curvature information to maintain positive definite approximations, our algorithms directly incorporate Hessian samples to update indefinite inverse Hessian approximations without filtering. The sampled directions supplement the standard QN two-dimensional trust-region sub-problem to generate a moderate dimensional subproblem which can exploit negative curvature. The resulting quadratically-constrained quadratic program is solved accurately with a generalized eigenvalue algorithm and the step advanced using standard trust region step acceptance and radius adjustments. The article aims to avoid serial bottlenecks, exploit accurate positive and negative curvature information, and conduct a preliminary evaluation of selection strategies for $S$.

【2】 Recovery of wave speeds and density of mass across a heterogeneous smooth interface from acoustic and elastic wave reflection operators
标题:用声波和弹性波反射算子恢复非均匀光滑界面上的波速和质量密度

链接:https://arxiv.org/abs/2201.02607
作者:Sombuddha Bhattacharyya,Maarten V. de Hoop,Vitaly Katsnelson,Gunther Uhlmann
备注:submitted for journal publication 10/21/2021; 42 pages
摘要:We revisit the problem of recovering wave speeds and density across a curved interface from reflected wave amplitudes. Such amplitudes have been exploited for decades in (exploration) seismology in this context. However, the analysis in seismology has been based on linearization and mostly flat interfaces. Here, we present a nonlinear analysis allowing curved interfaces, establish uniqueness and provide a reconstruction, while making the notion of amplitude precise through a procedure rooted in microlocal analysis.

【3】 Wavenumber-explicit hp-FEM analysis for Maxwell's equations with impedance boundary conditions
标题:阻抗边界条件下麦克斯韦方程的波数显式hp-FEM分析

链接:https://arxiv.org/abs/2201.02602
作者:Jens M. Melenk,Stefan A. Sauter
备注:80 pages, 6 figures
摘要:The time-harmonic Maxwell equations at high wavenumber k in domains with an analytic boundary and impedance boundary conditions are considered. A wavenumber-explicit stability and regularity theory is developed that decomposes the solution into a part with finite Sobolev regularity that is controlled uniformly in k and an analytic part. Using this regularity, quasi-optimality of the Galerkin discretization based on Nedelec elements of order p on a mesh with mesh size h is shown under the k-explicit scale resolution condition that a) kh/p is sufficient small and b) p/\ln k is bounded from below.

【4】 Completeness of derived interleaving distances and sheaf quantization of non-smooth objects
标题:导出交织距离的完备性与非光滑物体的束量化

链接:https://arxiv.org/abs/2201.02598
作者:Tomohiro Asano,Yuichi Ike
备注:33 pages, 1 figure, comments are welcome
摘要:We investigate sheaf-theoretic methods to deal with non-smooth objects in symplectic geometry. We show the completeness of a derived category of sheaves with respect to the interleaving-like distance and construct a sheaf quantization of a hameomorphism. We also develop Lusternik-Schnirelmann theory in the microlocal theory of sheaves. With these new tools, we prove an Arnold-type theorem for the image of the zero-section under a hameomorphism by a purely sheaf-theoretic method.

【5】 Summation formulae for quadrics
标题:二次曲面的求和公式

链接:https://arxiv.org/abs/2201.02583
作者:Jayce R. Getz
摘要:We prove a Poisson summation formula for the zero locus of a quadratic form in an even number of variables with no assumption on the support of the functions involved. The key novelty in the formula is that all "boundary terms" are given either by constants or sums over smaller quadrics related to the original quadric. We also discuss the link with the classical problem of estimating the number of solutions of a quadratic form in an even number of variables. To prove the summation formula we compute (the Arthur truncated) theta lift of the trivial representation of $\mathrm{SL}_2(\mathbb{A}_F)$. As previously observed by Ginzburg, Rallis, and Soudry, this is an analogue for orthogonal groups on vector spaces of even dimension of the global Schr\"odinger representation of the metaplectic group.

【6】 The Inverse of the Incidence Matrix of a Unicyclic Graph
标题:单圈图的关联矩阵的逆

链接:https://arxiv.org/abs/2201.02580
作者:Ryan Hessert,Sudipta Mallik
摘要:The vertex-edge incidence matrix of a (connected) unicyclic graph G is a square matrix which is invertible if and only if the cycle of G is an odd cycle. A combinatorial formula of the inverse of the incidence matrix of an odd unicyclic graph was known. A combinatorial formula of the Moore-Penrose inverse of the incidence matrix of an even unicyclic graph is presented solving an open problem.

【7】 Incidence and Laplacian matrices of wheel graphs and their inverses
标题:轮图及其逆图的关联矩阵和拉普拉斯矩阵

链接:https://arxiv.org/abs/2201.02579
作者:Jerad Ipsen,Sudipta Mallik
摘要:It has been an open problem to find the Moore-Penrose inverses of the incidence, Laplacian, and signless Laplacian matrices of families of graphs except trees and unicyclic graphs. Since the inverse formulas for an odd unicyclic graph and an even unicyclic graph are quite different, we consider wheel graphs as they are formed from odd or even cycles. In this article solve the open problem for wheel graphs. This work has an interesting connection to inverses of circulant matrices.

【8】 Coarse Geometry of Pure Mapping Class Groups of Infinite Graphs
标题:无限图的纯映射类群的粗几何

链接:https://arxiv.org/abs/2201.02559
作者:George Domat,Hannah Hoganson,Sanghoon Kwak
备注:41 pages, 10 figures
摘要:We discuss the large-scale geometry of pure mapping class groups of locally finite, infinite graphs, motivated from recent work by Algom-Kfir--Bestvina and the work of Mann--Rafi on the large-scale geometry of mapping class groups of infinite-type surfaces. Using the framework of Rosendal for coarse geometry of non-locally compact groups, we classify when the pure mapping class group of a locally finite, infinite graph is globally coarsely bounded (an analog of compact) and when it is locally coarsely bounded (an analog of locally compact). Our techniques also give lower bounds on the first integral cohomology of the pure mapping class group for some graphs and show that some of these groups have continuous actions on simplicial trees.

【9】 Exponential multiple mixing for commuting automorphisms of a nilmanifold
标题:零流形交换自同构的指数多重混合

链接:https://arxiv.org/abs/2201.02556
作者:Timothée Bénard,Péter P. Varjú
备注:13 pages
摘要:Let $l\in \mathbb{N}_{\geq 1}$ and $\alpha : \mathbb{Z}^l\rightarrow \text{Aut}(\mathscr{N})$ be an action of $\mathbb{Z}^l$ by automorphisms on a compact nilmanifold $\mathscr{N}$. We assume the action of every $\alpha(z)$ is ergodic for $z\in \mathbb{Z}^l\smallsetminus\{0\}$ and show that $\alpha$ satisfies exponential $n$-mixing for any integer $n\geq 2$. This extends results of Gorodnik and Spatzier [Acta Math., 215 (2015)].

【10】 The Persistence Landscapes of Affine Fractals
标题:仿射分形的持久景观

链接:https://arxiv.org/abs/2201.02552
作者:Michael J. Catanzaro,Lee Przybylski,Eric S. Weber
备注:32 pages, 5 figures. Comments welcome
摘要:We develop a method for calculating the persistence landscapes of affine fractals using the parameters of the corresponding transformations. Given an iterated function system of affine transformations that satisfies a certain compatibility condition, we prove that there exists an affine transformation acting on the space of persistence landscapes which intertwines the action of the iterated function system. This latter affine transformation is a strict contraction and its unique fixed point is the persistence landscape of the affine fractal. We present several examples of the theory as well as confirm the main results through simulations.

【11】 Multiplication and convolution topological algebras in spaces of $ω$-ultradifferentiable functions of Beurling type
标题:$ω$-超可微Beuring型函数空间中的乘法和卷积拓扑代数

链接:https://arxiv.org/abs/2201.02549
作者:Angela A. Albanese,Claudio Mele
摘要:We determine multiplication and convolution topological algebras for classes of $\omega$-ultradifferentiable functions of Beurling type. Hypocontinuous and discontinuous mappings are investigated. It is also proved that the pre-dual $\mathcal{O}_{C,\omega}(\mathbb{R}^N)$ of the space of convolutors of $\mathcal{S}_\omega(\mathbb{R}^N)$ is a complete Montel space.

【12】 Standard Young tableaux and lattice paths
标题:标准Young画面和晶格路径

链接:https://arxiv.org/abs/2201.02540
作者:Shaun V. Ault
备注:9 pages, 3 figures
摘要:Using lattice path counting arguments, we reproduce a well known formula for the number of standard Young tableaux. We also produce an interesting new formula for tableaux of height $\leq 3$ using the Fourier methods of Ault and Kicey.

【13】 Machine-learning-based arc selection for constrained shortest path problems in column generation
标题:基于机器学习的列生成约束最短路径问题的圆弧选择

链接:https://arxiv.org/abs/2201.02535
作者:Mouad Morabit,Guy Desaulniers,Andrea Lodi
摘要:Column generation is an iterative method used to solve a variety of optimization problems. It decomposes the problem into two parts: a master problem, and one or more pricing problems (PP). The total computing time taken by the method is divided between these two parts. In routing or scheduling applications, the problems are mostly defined on a network, and the PP is usually an NP-hard shortest path problem with resource constraints. In this work, we propose a new heuristic pricing algorithm based on machine learning. By taking advantage of the data collected during previous executions, the objective is to reduce the size of the network and accelerate the PP, keeping only the arcs that have a high chance to be part of the linear relaxation solution. The method has been applied to two specific problems: the vehicle and crew scheduling problem in public transit and the vehicle routing problem with time windows. Reductions in computational time of up to 40% can be obtained.

【14】 Semilinear Li & Yau inequalities
标题:半线性Li&Yau不等式

链接:https://arxiv.org/abs/2201.02530
作者:Daniele Castorina,Giovanni Catino,Carlo Mantegazza
摘要:We derive an adaptation of Li & Yau estimates for positive solutions of semilinear heat equations on Riemannian manifolds with nonnegative Ricci tensor. We then apply these estimates to obtain a Harnack inequality and to discuss monotonicity, convexity, decay estimates and triviality of ancient and eternal solutions.

【15】 Singularity models in the three-dimensional Ricci flow
标题:三维Ricci流中的奇点模型

链接:https://arxiv.org/abs/2201.02522
作者:S. Brendle
备注:This is survey paper which will appear in the KIAS Expositions
摘要:The Ricci flow is a natural evolution equation for Riemannian metrics on a given manifold. The main goal is to understand singularity formation. In his spectacular 2002 breakthrough, Perelman achieved a qualitative understanding of singularity formation in dimension $3$. More precisely, Perelman showed that every finite-time singularity to the Ricci flow in dimension $3$ is modeled on an ancient $\kappa$-solution. Moreover, Perelman proved a structure theorem for ancient $\kappa$-solutions in dimension $3$. In this survey, we will discuss recent developments which have led to a complete classification of all the singularity models in dimension $3$. Moreover, we give an alternative proof of the classification of noncollapsed steady gradient Ricci solitons in dimension $3$ (originally proved by the author in 2012).

【16】 Four Blocks Cycles C(k,1,1,1) in Digraphs
标题:有向图中的四块圈C(k,1,1,1)

链接:https://arxiv.org/abs/2201.02520
作者:Zahraa Mohsen
摘要:A four blocks cycle C(k1,k2,k3,k4) is an oriented cycle formed by the union of four internally disjoint directed paths of lengths k1,k2,k3 and k4 respectively. El Mniny proved that if D is a digraph having a spanning out-tree T with no subdivisions of C(k, 1, 1, 1), then the chromatic number of D is at most 8^{3}k. In this paper, we will improve this bound to 18k.

【17】 Skew Dyck paths with catastrophes
标题:具有灾变的偏向Dyck路径

链接:https://arxiv.org/abs/2201.02518
作者:Helmut Prodinger
摘要:Skew Dyck paths are like Dyck paths, but an additional south-west step $(-1,-1)$ is allowed, provided that the path does not intersect itself. Lattice paths with catastrophes can drop from any level to the origin in just one step. We combine these two ideas. The analysis is strictly based on generating functions, and the kernel method is used.

【18】 The Efficiency of the ANS Entropy Encoding

链接:https://arxiv.org/abs/2201.02514
作者:Dmitry Kosolobov
备注:15 pages, 5 figures, 2 algorithms
摘要:The Asymmetric Numeral Systems (ANS) is a class of entropy encoders by Duda that had an immense impact on the data compression, substituting arithmetic and Huffman coding. The optimality of ANS was studied by Duda et al. but the precise asymptotic behaviour of its redundancy (in comparison to the entropy) was not completely understood. In this paper we establish an optimal bound on the redundancy for the tabled ANS (tANS), the most popular ANS variant. Given a sequence $a_1,\ldots,a_n$ of letters from an alphabet $\{0,\ldots,\sigma-1\}$ such that each letter $a$ occurs in it $f_a$ times and $n=2^r$, the tANS encoder using Duda's ``precise initialization'' to fill tANS tables transforms this sequence into a bit string of length (frequencies are not included in the encoding size): $$ \sum\limits_{a\in [0..\sigma)}f_a\cdot\log\frac{n}{f_a}+O(\sigma+r), $$ where $O(\sigma + r)$ can be bounded by $\sigma\log e+r$. The $r$-bit term is an encoder artifact indispensable to ANS; the rest incurs a redundancy of $O(\frac{\sigma}{n})$ bits per letter. We complement this bound by a series of examples showing that an $\Omega(\sigma+r)$ redundancy is necessary when $\sigma > n/3$, where $\Omega(\sigma + r)$ is at least $\frac{\sigma-1}{4}+r-2$. We argue that similar examples exist for any methods that distribute letters in tANS tables using only the knowledge about frequencies. Thus, we refute Duda's conjecture that the redundancy is $O(\frac{\sigma}{n^2})$ bits per letter. We also propose a new variant of range ANS (rANS), called rANS with fixed accuracy, that is parameterized by $k \ge 1$. In this variant the integer division, which is unavoidable in rANS, is performed only in cases when its result belongs to $[2^k..2^{k+1})$. Hence, the division can be computed by faster methods provided $k$ is small. We bound the redundancy for the rANS with fixed accuracy $k$ by $\frac{n}{2^k-1}\log e+r$.

【19】 The automorphism groups of Artin groups of edge-separated CLTTF graphs
标题:边分离CLTTF图的Artin群的自同构群

链接:https://arxiv.org/abs/2201.02502
作者:Byung Hee An,Youngjin Cho
备注:30 pages, 6 figures
摘要:We provide an explicit presentation of the automorphism group of an edge-separated CLTTF Artin group.

【20】 On the Distance Spectra of Extended Double Stars
标题:关于扩展双星的距离谱

链接:https://arxiv.org/abs/2201.02499
作者:Anuj Sakarda,Jerry Tan,Armaan Tipirneni
备注:13 pages, 13 figures, arXiv:1307.5931, arXiv:1606.07551, To be presented at JMM 2022
摘要:The distance matrix of a connected graph is defined as the matrix in which the entries are the pairwise distances between vertices. The distance spectrum of a graph is the set of eigenvalues of its distance matrix. A graph is said to be determined by its distance spectrum if there does not exist a non-isomorphic graph with the same spectrum. The question of which graphs are determined by their spectrum has been raised in the past, but it remains largely unresolved. In this paper, we prove that extended double stars are determined by their distance spectra.

【21】 Cauchy, normal and correlations versus heavy tails
标题:柯西,正态和相关性与重尾

链接:https://arxiv.org/abs/2201.02498
作者:Hui Xu,Joel Cohen,Richard Davis,Gennady Samorodnitsky
摘要:A surprising result of Pillai and Meng (2016) showed that a transformation $\sum_{j=1}^n w_j X_j/Y_j$ of two iid centered normal random vectors, $(X_1,\ldots, X_n)$ and $(Y_1,\ldots, Y_n)$, $n>1$, for any weights $0\leq w_j\leq 1$, $ j=1,\ldots, n$, $\sum_{j=1}^n w_j=1$, has a Cauchy distribution regardless of any correlations within the normal vectors. The correlations appear to lose out in the competition with the heavy tails. To clarify how extensive this phenomenon is, we analyze two other transformations of two iid centered normal random vectors. These transformations are similar in spirit to the transformation considered by Pillai and Meng (2016). One transformation involves absolute values: $\sum_{j=1}^n w_j X_j/|Y_j|$. The second involves randomly stopped Brownian motions: $\sum_{j=1}^n w_j X_j\bigl(Y_j^{-2}\bigr)$, where $\bigl\{\bigl( X_1(t),\ldots, X_n(t)\bigr), \, t\geq 0\bigr\},\ n>1,$ is a Brownian motion with positive variances; $(Y_1,\ldots, Y_n)$ is a centered normal random vector with the same law as $( X_1(1),\ldots, X_n(1))$ and independent of it; and $X(Y^{-2})$ is the value of the Brownian motion $X(t)$ evaluated at the random time $t=Y^{-2}$. All three transformations result in a Cauchy distribution if the covariance matrix of the normal components is diagonal, or if all the correlations implied by the covariance matrix equal 1. However, while the transformation Pillai and Meng (2016) considered produces a Cauchy distribution regardless of the normal covariance matrix. the transformations we consider here do not always produce a Cauchy distribution. The correlations between jointly normal random variables are not always overwhelmed by the heaviness of the marginal tails. The mysteries of the connections between normal and Cauchy laws remain to be understood.

【22】 TOWER-Complete Problems in Contraction-Free Substructural Logics
标题:无收缩子结构逻辑中的塔式完备性问题

链接:https://arxiv.org/abs/2201.02496
作者:Hiromi Tanaka
备注:Draft
摘要:We investigate the computational complexity of a family of substructural logics with exchange and weakening but without contraction. With the aid of the techniques provided by Lazi\'c and Schmitz (2015), we show that the deducibility problem for full Lambek calculus with exchange and weakening ($\mathbf{FL}_{\mathbf{ew}}$) is TOWER-complete, where TOWER is one of the non-elementary complexity classes introduced by Schmitz (2016). The same complexity result holds even for deducibility in BCK-logic, i.e., the implicational fragment of $\mathbf{FL}_{\mathbf{ew}}$. We furthermore show the TOWER-completeness of the provability problem for elementary affine logic, which was proved to be decidable by Dal Lago and Martini (2004).

【23】 An efficient and easy-to-extend Matlab code of the Moving Morphable Component (MMC) method for three-dimensional topology optimization
标题:一种高效、易扩展的移动可变形分量(MMC)三维拓扑优化Matlab代码

链接:https://arxiv.org/abs/2201.02491
作者:Zongliang Du,Tianchen Cui,Chang Liu,Weisheng Zhang,Yilin Guo,Xu Guo
摘要:Explicit topology optimization methods have received ever-increasing interest in recent years. In particular, a 188-line Matlab code of the two-dimensional (2D) Moving Morphable Component (MMC)-based topology optimization method was released by Zhang et al. (Struct Multidiscip Optim 53(6):1243-1260, 2016). The present work aims to propose an efficient and easy-to-extend 256-line Matlab code of the MMC method for three-dimensional (3D) topology optimization implementing some new numerical techniques. To be specific, by virtue of the function aggregation technique, accurate sensitivity analysis, which is also easy-to-extend to other problems, is achieved. Besides, based on an efficient loading path identification algorithm, the degrees of freedoms (DOFs) not belonging to the loading path are removed in finite element analysis (FEA), which significantly accelerates the optimization process. As a result, compared to the corresponding 188-line 2D code, the performance of the optimization results, the computational efficiency of FEA, and the convergence rate and the robustness of optimization process are greatly improved. For the sake of completeness, a refined 218-line Matlab code implementing the 2D-MMC method is also provided.

【24】 de Finetti-type theorems on quasi-local algebras and infinite Fermi tensor products
标题:关于拟局部代数和无限费米张量积的de Finetti型定理

链接:https://arxiv.org/abs/2201.02488
作者:Vitonofrio Crismale,Stefano Rossi,Paola Zurlo
备注:31 pages
摘要:Local actions of $\mathbb{P}_\mathbb{N}$, the group of finite permutations on $\mathbb{N}$, on quasi-local algebras are defined and proved to be $\mathbb{P}_\mathbb{N}$-abelian. It turns out that invariant states under local actions are automatically even, and extreme invariant states are strongly clustering. Tail algebras of invariant states are shown to obey a form of the Hewitt and Savage theorem, in that they coincide with the fixed-point von Neumann algebra. Infinite graded tensor products of $C^*$-algebras, which include the CAR algebra, are then addressed as particular examples of quasi-local algebras acted upon $\mathbb{P}_\mathbb{N}$ in a natural way. Extreme invariant states are characterized as infinite products of a single even state, and a de Finetti theorem is established. Finally, infinite products of factorial even states are shown to be factorial by applying a twisted version of the tensor product commutation theorem, which is also derived here.

【25】 Hardy inequalities for magnetic $p$-Laplacians
标题:磁性$p$-Laplacian的Hardy不等式

链接:https://arxiv.org/abs/2201.02482
作者:Cristian Cazacu,David Krejcirik,Ari Laptev
备注:20 pages
摘要:Improved Hardy inequalities for the $p$-Laplacian due to adding magnetic fields are established, while other expected results are stated as conjectures. Some general $L^p$ magnetic-free Hardy inequalities in the spirit of Allegretto and Huang [Nonlinear Anal. 32 (1998)] are also considered.

【26】 Neighborly partitions and the numerators of Rogers-Ramanujan identities
标题:邻域划分与Rogers-Ramanujan恒等式的分子

链接:https://arxiv.org/abs/2201.02481
作者:Zahraa Mohsen,Hussein Mourtada
摘要:We prove two partition identities which are dual to the Rogers-Ramanujan identities. These identities are inspired by (and proved using) a correspondence between three kinds of objects: a new type of partitions (neighborly partitions), monomial ideals and some infinite graphs.

【27】 On The Decoding Error Weight of One or Two Deletion Channels

链接:https://arxiv.org/abs/2201.02466
作者:Omer Sabary,Daniella Bar-Lev,Yotam Gershon,Alexander Yucovich,Eitan Yaakobi
备注:arXiv admin note: text overlap with arXiv:2001.05582
摘要:This paper tackles two problems that are relevant to coding for insertions and deletions. These problems are motivated by several applications, among them is reconstructing strands in DNA-based storage systems. Under this paradigm, a word is transmitted over some fixed number of identical independent channels and the goal of the decoder is to output the transmitted word or some close approximation of it. The first part of this paper studies the deletion channel that deletes a symbol with some fixed probability $p$, while focusing on two instances of this channel. Since operating the maximum likelihood (ML) decoder in this case is computationally unfeasible, we study a slightly degraded version of this decoder for two channels and its expected normalized distance. We identify the dominant error patterns and based on these observations, it is derived that the expected normalized distance of the degraded ML decoder is roughly $\frac{3q-1}{q-1}p^2$, when the transmitted word is any $q$-ary sequence and $p$ is the channel's deletion probability. We also study the cases when the transmitted word belongs to the Varshamov Tenengolts (VT) code or the shifted VT code. Additionally, the insertion channel is studied as well as the case of two insertion channels. These theoretical results are verified by corresponding simulations. The second part of the paper studies optimal decoding for a special case of the deletion channel, the $k$-deletion channel, which deletes exactly $k$ symbols of the transmitted word uniformly at random. In this part, the goal is to understand how an optimal decoder operates in order to minimize the expected normalized distance. A full characterization of an efficient optimal decoder for this setup, referred to as the maximum likelihood* (ML*) decoder, is given for a channel that deletes one or two symbols.

【28】 Triangles in intersecting families
标题:相交族中的三角形

链接:https://arxiv.org/abs/2201.02452
作者:Dániel T. Nagy,Balázs Patkós
备注:7 pages
摘要:We prove the following the generalized Tur\'an type result. A collection $\mathcal{T}$ of $r$ sets is an $r$-triangle if for every $T_1,T_2,\dots,T_{r-1}\in \mathcal{T}$ we have $\cap_{i=1}^{r-1}T_i\neq\emptyset$, but $\cap_{T\in \mathcal{T}}T$ is empty. A family $\mathcal{F}$ of sets is $r$-wise intersecting if for any $F_1,F_2,\dots,F_r\in \mathcal{F}$ we have $\cap_{i=1}^rF_i\neq \emptyset$ or equivalently if $\mathcal{F}$ does not contain any $m$-triangle for $m=2,3,\dots,r$. We prove that if $n\ge n_0(r,k)$, then the $r$-wise intersecting family $\mathcal{F}\subseteq \binom{[n]}{k}$ containing the most number of $(r+1)$-triangles is isomorphic to $\{F\in \binom{[n]}{k}:|F\cap [r+1]|\ge r\}$.

【29】 Analytical calculation formulas for capacities of classical and classical-quantum channels

链接:https://arxiv.org/abs/2201.02450
作者:Masahito Hayashi
摘要:We derive an analytical calculation formula for the channel capacity of a classical channel without any iteration while its existing algorithms require iterations and the number of iteration depends on the required precision level. Hence, our formula is its first analytical formula without any iteration. We apply the obtained formula to examples and see how the obtained formula works in these examples. Then, we extend it to the channel capacity of a classical-quantum (cq-) channel. Many existing studies proposed algorithms for a cq-channel and all of them require iterations. Our extended analytical algorithm have also no iteration and output the exactly optimum values.

【30】 Bregman divergence based em algorithm and its application to classical and quantum rate distortion theory

链接:https://arxiv.org/abs/2201.02447
作者:Masahito Hayashi
摘要:We formulate em algorithm in the framework of Bregman divergence, which is a general problem setting of information geometry. That is, we address the minimization problem of the Bregman divergence between an exponential subfamily and a mixture subfamily in a Bregman divergence system. Then, we show the convergence and its speed under several conditions. We apply this algorithm to rate distortion and its variants including the quantum setting, and show the usefulness of our general algorithm.

【31】 Graded irreducible representations of Leavitt path algebras: a new type and complete classification
标题:Leavitt路代数的分次不可约表示:一种新的完全分类

链接:https://arxiv.org/abs/2201.02446
作者:Lia Vas
摘要:We present a new class of graded irreducible representations of a Leavitt path algebra. This class is new in the sense that its representation space is not isomorphic to any of the existing simple Chen modules. The corresponding graded simple modules complete the list of Chen modules which are graded, creating an exhaustive class: the annihilator of any graded simple module is equal to the annihilator of either a graded Chen module or a module of this new type. Our characterization of graded primitive ideals of a Leavitt path algebra in terms of the properties of the underlying graph is the main tool for proving the completeness of such classification. We also point out a problem with the characterization of primitive ideals of a Leavitt path algebra in [K. M. Rangaswamy, Theory of prime ideals of Leavitt path algebras over arbitrary graphs, J. Algebra 375 (2013), 73 -- 90].

【32】 Indefinite least squares with a quadratic constraint
标题:带二次约束的不定最小二乘法

链接:https://arxiv.org/abs/2201.02442
作者:Santiago Gonzalez Zerbo,Alejandra Maestripieri,Francisco Martínez Pería
备注:32 pages. Comments are welcomed!
摘要:An abstract indefinite least squares problem with a quadratic constraint is considered. This is a quadratic programming problem with one quadratic equality constraint, where neither the objective nor the constraint are convex functions. Necessary and sufficient conditions are found for the existence of solutions.

【33】 Linear pencils and quadratic programming problems with a quadratic constraint
标题:带二次约束的线性铅笔和二次规划问题

链接:https://arxiv.org/abs/2201.02439
作者:Santiago Gonzalez Zerbo,Alejandra Maestripieri,Francisco Martínez Pería
备注:24 pages. Comments are welcomed!
摘要:Given bounded selfadjoint operators $A$ and $B$ acting on a Hilbert space $\mathcal{H}$, consider the linear pencil $P(\lambda)=A+\lambda B$, $\lambda\in\mathbb{R}$. The set of parameters $\lambda$ such that $P(\lambda)$ is a positive (semi)definite operator is characterized. These results are applied to solving a quadratic programming problem with an equality quadratic constraint (or a QP1EQC problem).

【34】 Bases for infinite dimensional simple $\mathfrak{osp}(1|2n)$-modules respecting the branching $\mathfrak{osp}(1|2n)\supset \mathfrak{gl}(n)$

链接:https://arxiv.org/abs/2201.02438
作者:Asmus K. Bisbo,Joris Van der Jeugt
备注:31 pages
摘要:We study the effects of the branching $\mathfrak{osp}(1|2n)\supset \mathfrak{gl}(n)$ on a particular class of simple infinite-dimensional $\mathfrak{osp}(1|2n)$-modules $L(p)$ characterized by a positive integer $p$. In the first part we use combinatorial methods such as Young tableaux and Young subgroups to construct a new basis for $L(p)$ that respects this branching and we express the basis elements explicitly in two distinct ways. First as monomials of negative root vectors of $\mathfrak{gl}(n)$ acting on the $\mathfrak{gl}(n)$-highest weight vectors in $L(p)$ and then as polynomials in the generators of $\mathfrak{osp}(1|2n)$ acting on the $\mathfrak{osp}(1|2n)$-lowest weight vector in $L(p)$. In the second part we use extremal projectors and the theory of Mickelsson-Zhelobenko algebras to give new explicit constructions of raising and lowering operators related to the branching $\mathfrak{osp}(1|2n)\supset \mathfrak{gl}(n)$. We use the raising operators to give new expressions for the elements of the Gel'fand-Zetlin basis for $L(p)$ as monomials of operators from $U(\mathfrak{osp}(1|2n))$ acting on the $\mathfrak{osp}(1|2n)$-lowest weight vector in $L(p)$. We observe that the Gel'fand-Zetlin basis for $L(p)$ is related to the basis constructed earlier in the paper by a triangular transition matrix. We end the paper with a detailed example treating the case $n=3$.

【35】 On some problems regarding distance-balanced graphs
标题:关于距离平衡图的几个问题

链接:https://arxiv.org/abs/2201.02430
作者:Blas Fernandez,Ademir Hujdurovic
备注:16 pages
摘要:A graph $\Gamma$ is said to be distance-balanced if for any edge $uv$ of $\Gamma$, the number of vertices closer to $u$ than to $v$ is equal to the number of vertices closer to $v$ than to $u$, and it is called nicely distance-balanced if in addition this number is independent of the chosen edge $uv$. A graph $\Gamma$ is said to be strongly distance-balanced if for any edge $uv$ of $\Gamma$ and any integer $k$, the number of vertices at distance $k$ from $u$ and at distance $k+1$ from $v$ is equal to the number of vertices at distance $k+1$ from $u$ and at distance $k$ from $v$. In this paper we answer an open problem posed by Kutnar and Miklavi\v{c} [European J. Combin. 39 (2014), 57-67] by constructing several infinite families of nonbipartite nicely distance-balanced graphs which are not strongly distance-balanced. We disprove a conjecture regarding characterization of strongly distance-balanced graphs posed by Balakrishnan et al. [European J. Combin. 30 (2009), 1048-1053] by providing infinitely many counterexamples, and answer an open question posed by Kutnar et al. in [Discrete Math. 306 (2006), 1881-1894] regarding existence of semisymmetric distance-balanced graphs which are not strongly distance-balanced by providing an infinite family of such examples. We also show that for a graph $\Gamma$ with $n$ vertices and $m$ edges it can be checked in $O(mn)$ time if $\Gamma$ is strongly-distance balanced and in $O(m^2)$ time if $\Gamma$ is nicely distance-balanced.

【36】 An Adaptive Penalty Method for Inequality Constrained Minimization Problems
标题:不等式约束极小化问题的一种自适应惩罚方法

链接:https://arxiv.org/abs/2201.02425
作者:Wietse M. Boon,Jan M. Nordbotten
备注:None
摘要:The primal-dual active set method is observed to be the limit of a sequence of penalty formulations. Using this perspective, we propose a penalty method that adaptively becomes the active set method as the residual of the iterate decreases. The adaptive penalty method (APM) therewith combines the main advantages of both methods, namely the ease of implementation of penalty methods and the exact imposition of inequality constraints inherent to the active set method. The scheme can be considered a quasi-Newton method in which the Jacobian is approximated using a penalty parameter. This spatially varying parameter is chosen at each iteration by solving an auxiliary problem.

【37】 Fano manifolds with Lefschetz defect 3
标题:Lefschetz亏数为3的Fano流形

链接:https://arxiv.org/abs/2201.02413
作者:C. Casagrande,E. A. Romano,S. A. Secci
备注:30 pages, 2 figures
摘要:Let X be a smooth, complex Fano variety, and delta(X) its Lefschetz defect. It is known that if delta(X) is at least 4, then X is isomorphic to a product SxT, where dim T=dim X-2. In this paper we prove a structure theorem for the case where delta(X)=3. We show that there exists a smooth Fano variety T with dim T=dim X-2 such that X is obtained from T with two possible explicit constructions; in both cases there is a P^2-bundle Z over T such that X is the blow-up of Z along three pairwise disjoint smooth, irreducible, codimension 2 subvarieties. Then we apply the structure theorem to Fano 4-folds, to the case where X has Picard number 5, and to Fano varieties having an elementary divisorial contraction sending a divisor to a curve. In particular we complete the classification of Fano 4-folds with delta(X)=3.

【38】 Non-linear heat equation on the Hyperbolic space: Global existence and finite-time Blow-up
标题:双曲空间上非线性热方程的整体存在性和有限时间爆破

链接:https://arxiv.org/abs/2201.02400
作者:Debdip Ganguly,Debabrata Karmakar,Saikat Mazumdar
摘要:We consider the following Cauchy problem for the semi linear heat equation on the hyperbolic space: \begin{align}\label{abs:eqn} \left\{\begin{array}{ll} \partial_{t}u=\Delta_{\mathbb{H}^{n}} u+ f(u, t) &\hbox{ in }~ \mathbb{H}^{n}\times (0, T),\\ \\ \quad u =u_{0} &\hbox{ in }~ \mathbb{H}^{n}\times \{0\}. \end{array}\right. \end{align} We study Fujita phenomena for the non-negative initial data $u_0$ belonging to $C(\mathbb{H}^{n}) \cap L^{\infty}(\mathbb{H}^{n})$ and for different choices of $f$ of the form $f(u,t) = h(t)g(u).$ It is well-known that for power nonlinearities in $u,$ the power weight $h(t) = t^q$ is sub-critical in the sense that non-negative global solutions exist for small initial data. On the other hand, it exhibits Fujita phenomena for the exponential weight $h(t) = e^{\mu t},$ i.e. there exists a critical exponent $\mu^*$ such that if $\mu > \mu^*$ then all non-negative solutions blow-up in finite time and if $\mu \leq \mu^*$ there exists non-negative global solutions for small initial data. One of the main objectives of this article is to find an appropriate nonlinearity in $u$ so that the above mentioned Cauchy problem with the power weight $h(t) = t^q$ does exhibit Fujita phenomena. In the remaining part of this article, we study Fujita phenomena for exponential nonlinearity in $u.$ We further generalize some of these results to Cartan-Hadamard manifolds.

【39】 An extension of an asymptotic result of Tricomi concerning a definite integral
标题:Tricomi关于定积分的一个渐近结果的推广

链接:https://arxiv.org/abs/2201.02399
作者:R B Paris
备注:8 pages, 0 figures
摘要:We consider the expansion of an integral considered by F.G. Tricomi given by \[\int_{-\infty}^\infty x e^{-x^2}(\frac{1}{2}+\frac{1}{2}\mbox{erf}\,x)^{m} dx\] as $m\to\infty$. The procedure involves a suitable change of variable and the inversion of the complementary error function $\mbox{erfc}\,x$. Numerical results are presented to demonstrate the accuracy of the expansion. A second part examines an extension of an integral arising in airfoil theory.

【40】 On the theory of generalized Ulrich modules
标题:关于广义Ulrich模的理论

链接:https://arxiv.org/abs/2201.02398
作者:Cleto B. Miranda-Neto,Douglas S. Queiroz,Thyago S. Souza
备注:17 pages
摘要:In this paper we further develop the theory of generalized Ulrich modules over Cohen-Macaulay local rings introduced in 2014 by Goto, Ozeki, Takahashi, Watanabe and Yoshida. The term {\it generalized} refers to the fact that Ulrich modules are taken with respect to a zero-dimensional ideal which is not necessarily the maximal ideal, the latter situation corresponding to the classical theory from the 80's; despite the apparent naivety of the idea, this passage adds considerable depth to the theory and enlarges its horizon of applications. First, we address the problem of when the Hom functor preserves the Ulrich property, and in particular we study relations with semidualizing modules. Second, we explore horizontal linkage of Ulrich modules, which we use to provide a characterization of Gorensteiness. Finally, we investigate connections between Ulrich modules and modules with minimal multiplicity, including characterizations in terms of relative reduction numbers as well as the Castelnuovo-Mumford regularity of certain blowup modules.

【41】 Model-Free Nonlinear Feedback Optimization
标题:无模型非线性反馈优化

链接:https://arxiv.org/abs/2201.02395
作者:Zhiyu He,Saverio Bolognani,Jianping He,Florian Dörfler,Xinping Guan
摘要:Feedback optimization is a control paradigm that enables physical systems to autonomously reach efficient operating points. Its central idea is to interconnect optimization iterations in closed-loop with the physical plant. Since iterative gradient-based methods are extensively used to achieve optimality, feedback optimization controllers typically require the knowledge of the steady-state sensitivity of the plant, which may not be easily accessible in some applications. In contrast, in this paper we develop a model-free feedback controller for efficient steady-state operation of general dynamical systems. The proposed design consists in updating control inputs via gradient estimates constructed from evaluations of the nonconvex objective at the current input and at the measured output. We study the dynamic interconnection of the proposed iterative controller with a stable nonlinear discrete-time plant. For this setup, we characterize the optimality and the stability of the closed-loop behavior as functions of the problem dimension, the number of iterations, and the rate of convergence of the physical plant. To handle general constraints that affect multiple inputs, we enhance the controller with Frank-Wolfe type updates.

【42】 InRS: implementing the indicator function of NURBS-shaped planar domains
标题:INRS:实现NURBS形状平面域的指示器功能

链接:https://arxiv.org/abs/2201.02393
作者:Alvise Sommarivaa,Marco Vianello
摘要:We provide an algorithm that implements the indicator function of NURBS-shaped planar domains, tailored to the fast computation on huge point clouds, together with the corresponding Matlab code.

【43】 Schrodinger equations with very singular potentials in Lipschitz domains
标题:Lipschitz域上具有非常奇异位势的薛定谔方程

链接:https://arxiv.org/abs/2201.02390
作者:Moshe Marcus
备注:18 pages
摘要:Consider operators $L^{V}:=\Delta + V$ in a bounded Lipschitz domain $\Omega \subset \mathbb{R}^N$. Assume that $V\in C^{1,1}(\Omega)$ and $V$ satisfies $V(x) \leq \overline{a} \mathrm{dist}(x,\partial\Omega)^{-2}$ in $\Omega$ and a second condition that guarantees the existence of a ground state $\Phi_V$. If, for example, $V>0$ this condition reads $1(v)$>

【44】 Asymptotic shape of isolated magnetic domains
标题:孤立磁畴的渐近形状

链接:https://arxiv.org/abs/2201.02384
作者:Hans Knüpfer,Dominik Stantejsky
备注:27 pages, 2 figures
摘要:We investigate the energy of an isolated magnetized domain $\Omega \subset \mathbb{R}^n$ for $n=2,3$. In non-dimensionalized variables, the energy given by $$ \mathcal{E}(\Omega) \ = \ \int_{\mathbb{R}^n} |\nabla \chi_{\Omega}| \ dx + \int_{\mathbb{R}^n} |\nabla \Phi|^2 \ dx $$ penalizes the interfacial area of the domain as well as the energy of the corresponding magnetostatic field. Here, the magnetostatic potential $\Phi$ is determined by $\Delta \Phi = \partial_1 \chi_\Omega$, corresponding to uniform magnetization within the domain. We consider the macroscopic regime $|\Omega| \rightarrow \infty$, in which we derive compactness and $\Gamma$-limit for the cross-section of the anisotropically rescaled configuration. The limit energy is local and the limiting shape of minimizers can be calculated.

【45】 The regulator dominates the rank
标题:监管者占主导地位

链接:https://arxiv.org/abs/2201.02383
作者:Fabien Pazuki
摘要:After noticing that the regulator of a number field dominates the rank of its group of units, we bound from below the regulator of the Mordell-Weil group of elliptic curves over global function fields of characteristic $p\geq5$. The lower bound is an increasing function of the rank and of the height.

【46】 Diffeomorphisms of discs
标题:圆盘的微分同态

链接:https://arxiv.org/abs/2201.02380
作者:Oscar Randal-Williams
备注:Contributed to the Proceedings of the 2022 ICM
摘要:I describe what is currently known, for $d \geq 5$, about the rational homotopy type of the group of diffeomorphisms of the $d$-disc relative to its boundary, and the closely related group of homeomorphisms of $d$-dimensional Euclidean space.

【47】 Proving some conjectures on Kekulé numbers for certain benzenoids by using Chebyshev polynomials
标题:用切比雪夫多项式证明某些苯类的Kekulé数猜想

链接:https://arxiv.org/abs/2201.02376
作者:Guoce Xin,Yueming Zhong
备注:28 pages,3 figures, 1 table
摘要:In chemistry, Cyvin-Gutman enumerates Kekul\'{e} numbers for certain benzenoids and record it as $A050446$ on OEIS. This number is exactly the two variable array $T(n,m)$ defined by the recursion $T(n, m) = T(n, m-1) + \sum^{\lfloor\frac{n-1}{2}\rfloor}_{k=0} T(2k, m-1)T(n-1-2k, m)$, where $T(n,0)=T(0,m)=1$ for all nonnegative integers $m,n$. Interestingly, this number also appeared in the context of weighted graphs, graph polytopes, magic labellings, and unit primitive matrices, studied by different authors. Several interesting conjectures were made on the OEIS. These conjectures are related to both the row and column generating function of $T(n,m)$. In this paper, give explicit formula of the column generating function, which is also the generating function $F(n,x)$ studied by B\'{o}na, Ju, and Yoshida. We also get trig function representations by using Chebyshev polynomials of the second kind. This allows us to prove all these conjectures.

【48】 Not all nilpotent monoids are finitely related
标题:并非所有的幂零幺半群都是有限相关的

链接:https://arxiv.org/abs/2201.02375
作者:Markus Steindl
摘要:A finite semigroup is finitely related (has finite degree) if its term functions are determined by a finite set of finitary relations. For example, it is known that all nilpotent semigroups are finitely related. A nilpotent monoid is a nilpotent semigroup with adjoined identity. We show that every $4$-nilpotent monoid is finitely related. We also give an example of a $5$-nilpotent monoid that is not finitely related. This is the first known example where adjoining an identity to a finitely related semigroup yields a semigroup which is not finitely related. We also provide examples of finitely related semigroups which have subsemigroups, homomorphic images, and in particular Rees quotients, that are not finitely related.

【49】 The Green's function of the Lax-Wendroff and Beam-Warming schemes
标题:Lax-Wendroff和束温格式的格林函数

链接:https://arxiv.org/abs/2201.02371
作者:Jean-François Coulombel
摘要:We prove a sharp uniform generalized Gaussian bound for the Green's function of the Lax-Wendroff and Beam-Warming schemes. Our bound highlights the spatial region that leads to the well-known (rather weak) instability of these schemes in the maximum norm. We also recover uniform bounds in the maximum norm when these schemes are applied to initial data of bounded variation.

【50】 Control problem for quadratic parabolic differential equations with sensor sets of finite volume or anisotropically decaying density
标题:具有有限体积或各向异性衰减传感器组的二次抛物型微分方程的控制问题

链接:https://arxiv.org/abs/2201.02370
作者:Alexander Dicke,Albrecht Seelmann,Ivan Veselic
备注:35 pages
摘要:We prove observability and null-controllability for quadratic parabolic differential equations. The sensor set is allowed to have finite volume if the generator has trivial singular space $S$. In the case of generators with singular space $S \neq \{ 0 \}$ the sensor set is permitted to decay in directions determined by $S$. The proof is based on dissipation estimates for the quadratic differential operator with respect to spectral projections of partial harmonic oscillators and corresponding uncertainty relations.

【51】 Deligne-Beilinson cohomology of the universal K3 surface
标题:泛K3曲面的Deligne-Beilinson上同调

链接:https://arxiv.org/abs/2201.02367
作者:Zhiyuan Li,Xun Zhang
备注:26 pages, any comments are welcome!
摘要:O'Grady's generalized Franchetta conjecture (GFC) is concerned with codimension 2 algebraic cycles on universal polarized K3 surfaces. In \cite{BL17}, this conjecture has been studied in the Betti cohomology groups. Following a suggestion of Voisin, we investigate this problem in the Deligne-Beilinson (DB) cohomology groups. In this paper, we develop the theory of Deligne-Beilinson cohomology groups on separated (smooth) Deligne-Mumford stacks. Using the automorphic cohomology group and Noether-Lefschetz theory, we compute the 4-th DB-cohomology group of universal oriented polarized K3 surfaces with at worst an $A_1$-singularity and show that GFC for such family holds in DB-cohomology. In particular, this confirms O'Grady's original conjecture in DB cohomology.

【52】 The extent of saturation of induced ideals
标题:诱导理想的饱和程度

链接:https://arxiv.org/abs/2201.02364
作者:Kenta Tsukuura
摘要:We construct a model with a saturated ideal $I$ over $\mathcal{P}_{\kappa}\lambda$ and study the extent of saturation of $I$.

【53】 Concentration phenomena in Fitzhugh-Nagumo's equations: A mesoscopic approach
标题:Fitzhugh-Nagumo方程中的浓度现象:介观方法

链接:https://arxiv.org/abs/2201.02363
作者:Alain Blaustein,Francis Filbet
摘要:We consider a spatially extended mesoscopic FitzHugh-Nagumo model with strong local interactions and prove that its asymptotic limit converges towards the classical nonlocal reaction-diffusion FitzHugh-Nagumo system. As the local interactions strongly dominate, the weak solution to the mesoscopic equation under consideration converges to the local equilibrium, which has the form of Dirac distribution concentrated to an averaged membrane potential. Our approach is based on techniques widely developed in kinetic theory (Wasserstein distance, relative entropy method), where macroscopic quantities of the mesoscopic model are compared with the solution to the nonlocal reaction-diffusion system. This approach allows to make the rigorous link between microscopic and reaction-diffusion models.

【54】 On M-O.Ore determinants
标题:关于M-O矿的决定因素

链接:https://arxiv.org/abs/2201.02361
作者:Jean Fresnel,Michel Matignon
摘要:The existence of certain Fq-spaces of differential forms of the projective line over a field K containing Fq leads us to prove an identity linking the determinant of the Moore matrix of n indeterminates with the determinant of the Moore matrix of the cofactors of its first row. These same spaces give an interpretation of Elkies pairing in terms of residues of differential forms. This pairing puts in duality the Fq-vector space of the roots of a Fq-linear polynomial and that of the roots of its reversed polynomial.

【55】 A survey of Nevanlinna theory in the viewpoint of holomorphic forms
标题:从全纯形式看Nevanlinna理论

链接:https://arxiv.org/abs/2201.02360
作者:Xianjing Dong,Shuangshuang Yang
摘要:This paper revisits the Nevanlinna theory for meromorphic functions on $\mathbb C$ in the viewpoint of holomorphic forms. According to our observation, Nevanlinna's functions can be formulated by a holomorphic form. Applying this thought to Riemann surfaces, one then extends the definition of Nevanlinna's functions using a holomorphic form $\mathscr S$. With the new settings, an analogue of Nevanlinna theory on \emph{weak $\mathscr S$-exhausted Riemann surfaces} is obtained, which is viewed as a generalization of the classical Nevanlinna theory on $\mathbb C$ and $\mathbb D.$

【56】 Projective Embedding of Dynamical Systems: uniform mean field equations
标题:动力系统的射影嵌入:一致平均场方程

链接:https://arxiv.org/abs/2201.02355
作者:Francesco Caravelli,Fabio L. Traversa,Michele Bonnin,Fabrizio Bonani
备注:45 pages; one column; 10 figures;
摘要:We study embeddings of continuous dynamical systems in larger dimensions via projector operators. We call this technique PEDS, projective embedding of dynamical systems, as the stable fixed point of the dynamics are recovered via projection from the higher dimensional space. In this paper we provide a general definition and prove that for a particular type of projector operator of rank-1, the uniform mean field projector, the equations of motion become a mean field approximation of the dynamical system. While in general the embedding depends on a specified variable ordering, the same is not true for the uniform mean field projector. In addition, we prove that the original stable fixed points remain stable fixed points of the dynamics, saddle points remain saddle, but unstable fixed points become saddles.

【57】 On the intersection ideal graph of semigroups
标题:关于半群的交理想图

链接:https://arxiv.org/abs/2201.02346
作者:Barkha Baloda,Jitender Kumar
备注:2 figures. arXiv admin note: text overlap with arXiv:2110.14194
摘要:The intersection ideal graph $\Gamma(S)$ of a semigroup $S$ is a simple undirected graph whose vertices are all nontrivial left ideals of $S$ and two distinct left ideals $I, J$ are adjacent if and only if their intersection is nontrivial. In this paper, we investigate the connectedness of $\Gamma(S)$. We show that if $\Gamma(S)$ is connected then $diam(\Gamma(S)) \leq 2$. Further we classify the semigroups such that the diameter of their intersection graph is two. Other graph invariants, namely perfectness, planarity, girth, dominance number, clique number, independence number etc. are also discussed. Finally, if $S$ is union of $n$ minimal left ideals then we obtain the automorphism group of $\Gamma(S)$.

【58】 Automorphisms of left Ideal relation graph over full matrix ring
标题:全矩阵环上左理想关系图的自同构

链接:https://arxiv.org/abs/2201.02345
作者:Jitender Kumar,Barkha Baloda,Sanjeet Malhotra
摘要:The left-ideal relation graph on a ring $R$, denoted by $\overrightarrow{\Gamma_{l-i}}(R)$, is a directed graph whose vertex set is all the elements of $R$ and there is a directed edge from $x$ to a distinct $y$ if and only if the left ideal generated by $x$, written as $[x]$, is properly contained in the left ideal generated by $y$. In this paper, the automorphisms of $\overrightarrow{\Gamma_{l-i}}(R)$ are characterized, where $R$ is the ring of all $n \times n$ matrices over a finite field $F_q$. The undirected left relation graph, denoted by $\Gamma_{l-i}(M_n(F_q))$, is the simple graph whose vertices are all the elements of $R$ and two distinct vertices $x, y$ are adjacent if and only if either $[x] \subset [y]$ or $[y] \subset [x]$ is considered. Various graph theoretic properties of $\Gamma_{l-i}(M_n(F_q))$ including connectedness, girth, clique number, etc. are studied.

【59】 Existence and multiplicity of solutions to a Kirchhoff type elliptic system with Trudinger-Moser growth
标题:具有Trudinger-Moser增长的Kirchhoff型椭圆方程解的存在性和多解性

链接:https://arxiv.org/abs/2201.02342
作者:Shengbing Deng,Xingliang Tian
摘要:This paper deals with the existence and multiplicity of solutions for a class of Kirchhoff type elliptic system involving the Trudinger-Moser exponential growth nonlinearities. We first study the existence of solutions for the following system \begin{eqnarray*} \left\{ \arraycolsep=1.5pt \begin{array}{ll} -\big(a_1+b_1\|u\|^{2(\theta_1-1)}\big)\Delta u= \lambda H_u(x,u,v)\ \ \ &\ \mbox{in}\ \ \ \Omega,\\[2mm] -\big(a_2+b_2\|v\|^{2(\theta_2-1)}\big)\Delta v= \lambda H_v(x,u,v)\ \ \ &\ \mbox{in}\ \ \ \Omega,\\[2mm] u=0, v=0\ \ \ \ &\ \mbox{on}\ \ \ \partial\Omega, \end{array} \right. \end{eqnarray*} where $\Omega$ is a bounded domain in $\mathbb{R}^2$ with smooth boundary,\ $\|u\|=\big(\int_{\Omega}|\nabla u|^2dx\big)^{1/2}$, $H_u$ and $H_v$ behave like $e^{\beta |s|^2}$ when $|s|\rightarrow \infty$ for some $\beta>0$, $a_1,\ a_2>0$, $b_1,\ b_2> 0$, $\theta_1,\ \theta_2> 1$ and $\lambda$ is a positive parameter. In the later part of the paper, we also discuss a new multiplicity result for the above system with a positive parameter induced by the nonlocal dependence. The Kirchhoff term and the lack of compactness of the associated energy functional due to the Trudinger-Moser embedding have to be overcome via some new techniques.

【60】 On a nonhomogeneous Kirchhoff type elliptic system with the singular Trudinger-Moser growth
标题:具有奇异Trudinger-Moser增长的非齐次Kirchhoff型椭圆组

链接:https://arxiv.org/abs/2201.02338
作者:Shengbing Deng,Xingliang Tian
摘要:The aim of this paper is to study the multiplicity of solutions for the following Kirchhoff type elliptic systems \begin{eqnarray*} \left\{ \arraycolsep=1.5pt \begin{array}{ll} -m\left(\sum^k_{j=1}\|u_j\|^2\right)\Delta u_i=\frac{f_i(x,u_1,\ldots,u_k)}{|x|^\beta}+\varepsilon h_i(x),\ \ & \mbox{in}\ \ \Omega, \ \ i=1,\ldots,k ,\\[2mm] u_1=u_2=\cdots=u_k=0,\ \ & \mbox{on}\ \ \partial\Omega, \end{array} \right. \end{eqnarray*} where $\Omega$ is a bounded domain in $\mathbb{R}^2$ containing the origin with smooth boundary, $\beta\in [0,2)$, $m$ is a Kirchhoff type function, $\|u_j\|^2=\int_\Omega|\nabla u_j|^2dx$, $f_i$ behaves like $e^{\beta s^2}$ when $|s|\rightarrow \infty$ for some $\beta>0$, and there is $C^1$ function $F: \Omega\times\mathbb{R}^k\to \mathbb{R}$ such that $\left(\frac{\partial F}{\partial u_1},\ldots,\frac{\partial F}{\partial u_k}\right)=\left(f_1,\ldots,f_k\right)$, $h_i\in \left(\big(H^1_0(\Omega)\big)^*,\|\cdot\|_*\right)$. We establish sufficient conditions for the multiplicity of solutions of the above system by using variational methods with a suitable singular Trudinger-Moser inequality when $\varepsilon>0$ is small.

【61】 Classical and quantum walks on paths associated with exceptional Krawtchouk polynomials

链接:https://arxiv.org/abs/2201.02337
作者:Hiroshi Miki,Satoshi Tsujimoto,Luc Vinet
备注:22 pages, 4 figures
摘要:Classical and quantum walks on some finite paths are introduced. It is shown that these walks have explicit solutions given in terms of exceptional Krawtchouk polynomials and their properties are explored. In particular, fractional revival is shown to take place in the corresponding quantum walks.

【62】 On f-Derangements and Decomposing Bipartite Graphs into Paths
标题:关于f-乱列与二部图的路分解

链接:https://arxiv.org/abs/2201.02332
作者:Michael Plantholt,Hamidreza Habibi,Benjamin Mussell
摘要:Let $f: \{1, ..., n\} \rightarrow \{1, ..., n\}$ be a function (not necessarily one-to-one). An $f-derangement$ is a permutation $ g:\{1,...,n\} \rightarrow \{1,...,n\}$ such that $g(i) \neq f(i)$ for each $ i = 1, ..., n$. When $f$ is itself a permutation, this is a standard derangement. We examine properties of f-derangements, and show that when we fix the maximum number of preimages for any item under $f$, the fraction of permutations that are f-derangements tends to $ 1/e$ for large $n$, regardless of the choice of $f$. We then use this result to analyze a heuristic method to decompose bipartite graphs into paths of length 5

【63】 Asymptotic slopes and strong semistability on surfaces
标题:曲面上的渐近斜率与强半稳定性

链接:https://arxiv.org/abs/2201.02329
作者:Mitra Koley,A. J. Parameswaran
备注:Comments welcome
摘要:In this article we study asymptotic slopes of strongly semistable vector bundles on a smooth projective surface. A connection between asymptotic slopes and strong restriction theorem of a strongly semistable vector bundle is shown. We also give an equivalent criterion of strong semistability of a vector bundle in terms of its asymptotic slopes under some assumptions on the surface and on the bundle.

【64】 Prikry-type forcing and the set of possible cofinalities
标题:Prikry型强迫与可能余定集

链接:https://arxiv.org/abs/2201.02322
作者:Kenta Tsukuura
摘要:It is known that the set of possible cofinalities $\mathrm{pcf}(A)$ has good properties if $A$ is a progressive interval of regular cardinals. In this paper, we give an interval of regular cardinals $A$ such that $\mathrm{pcf}(A)$ has no good properties in the presense of a measurable cardinal, or in generic extensions by Prikry-type forcing.

【65】 Spatial integral of the solution to hyperbolic Anderson model with time-independent noise
标题:带时间无关噪声的双曲型Anderson模型解的空间积分

链接:https://arxiv.org/abs/2201.02319
作者:Raluca M. Balan,Wangjun Yuan
备注:43 pages
摘要:In this article, we study the asymptotic behavior of the spatial integral of the solution to the hyperbolic Anderson model in dimension $d\leq 2$, as the domain of the integral gets large (for fixed time $t$). This equation is driven by a spatially homogeneous Gaussian noise, whose covariance function is either integrable, or is given by the Riesz kernel. The novelty is that the noise does not depend on time, which means that It\^o's martingale theory for stochastic integration cannot be used. Using a combination of Malliavin calculus with Stein's method, we show that with proper normalization and centering, the spatial integral of the solution converges to a standard normal distribution, by estimating the speed of this convergence in the total variation distance. We also prove the corresponding functional limit theorem for the spatial integral process.

【66】 Stochastic Saddle Point Problems with Decision-Dependent Distributions
标题:决策相关分布的随机鞍点问题

链接:https://arxiv.org/abs/2201.02313
作者:Killian Wood,Emiliano Dall'Anese
摘要:This paper focuses on stochastic saddle point problems with decision-dependent distributions in both the static and time-varying settings. These are problems whose objective is the expected value of a stochastic payoff function, where random variables are drawn from a distribution induced by a distributional map. For general distributional maps, the problem of finding saddle points is in general computationally burdensome, even if the distribution is known. To enable a tractable solution approach, we introduce the notion of equilibrium points -- which are saddle points for the stationary stochastic minimax problem that they induce -- and provide conditions for their existence and uniqueness. We demonstrate that the distance between the two classes of solutions is bounded provided that the objective has a strongly-convex-strongly-concave payoff and Lipschitz continuous distributional map. We develop deterministic and stochastic primal-dual algorithms and demonstrate their convergence to the equilibrium point. In particular, by modeling errors emerging from a stochastic gradient estimator as sub-Weibull random variables, we provide error bounds in expectation and in high probability that hold for each iteration; moreover, we show convergence to a neighborhood in expectation and almost surely. Finally, we investigate a condition on the distributional map -- which we call opposing mixture dominance -- that ensures the objective is strongly-convex-strongly-concave. Under this assumption, we show that primal-dual algorithms converge to the saddle points in a similar fashion.

【67】 Electric Vehicle Routing Problem with Spatio-temporal Varying Electricity Price and Incentive-aware Customers
标题:具有时空变化电价和激励顾客的电动汽车路径问题

链接:https://arxiv.org/abs/2201.02311
作者:Canqi Yao,Shibo Chen,Mauro Salazar,Zaiyue Yang
备注:Submitted to IEEE TSG. arXiv admin note: substantial text overlap with arXiv:2110.06441
摘要:This paper investigates the optimization problem of a fleet of electric vehicles (EVs) serving a set of time-specified customers, where the operator needs to optimize routing and charging problem jointly for each EV. In particular, regarding to the spatio-temporal varying electricity price, we consider incentive-aware customers and propose that the operator offers monetary incentives to exchange time flexibility of customers. In this manner, a win-win situation is achievable since time flexibility enables the fleet operator to obtain a routing and charging schedule with lower cost, whilst the customers receives monetary compensation. Specifically, we first devise a bi-level model whereby the fleet operator optimizes the routing and charging schedule jointly with a monetary incentive to reimburse the delivery time flexibility experienced by the customers. At the same time, the customers choose the optimal time flexibility by minimizing its own cost. Second, we tackle the complexity resulting from the bi-level and nonlinear problem with an equivalent transformation method. Eventually, we reformulate the problem as a single-level optimization problem, which later is solved by proposed Benders dual decomposition method holding a faster convergence rate than the generalized Benders decomposition method. To evaluate the effectiveness of our framework and proposed Benders dual decomposition algorithm, we carry out extensive numerical experiments using VRP-REP data from Belgium.

【68】 Systems of equations over the group ring of Thompson's group $F$
标题:Thompson群的群环上的方程组$F$

链接:https://arxiv.org/abs/2201.02308
作者:Victor Guba
备注:arXiv admin note: text overlap with arXiv:2101.01848
摘要:Let $R=K[G]$ be a group ring of a group $G$ over a field $K$. It is known that if $G$ is amenable then $R$ satisfies the Ore condition: for any $a,b\in R$ there exist $u,v\in R$ such that $au=bv$, where $u\ne0$ or $v\ne0$. It is also true for amenable groups that a non-zero solution exists for any finite system of linear equations over $R$, where the number of unknowns exceeds the number of equations. Recently Bartholdi proved the converse. As a consequence of this theorem, Kielak proved that R.\,Thompson's group $F$ is amenable if and only if it satisfies the Ore condition. The amenability problem for $F$ is a long-standing open question. In this paper we prove that some equations or their systems have non-zero solutions in the group rings of $F$. We improve some results by Donnelly showing that there exist finite sets $Y\subset F$ with the property $|AY| < \frac43|Y|$, where $A=\{x_0,x_1,x_2\}$. This implies some result on the systems of equations. We show that for any element $b$ in the group ring of $F$, the equation $(1-x_0)u=bv$ has a non-zero solution. The corresponding fact for $1-x_1$ instead of $1-x_0$ remains open. We deduce that for any $m\ge1$ the system $(1-x_0)u_0=(1-x_1)u_1=\cdots=(1-x_m)u_m$ has nonzero solutions in the group ring of $F$. We also analyze the equation $(1-x_0)u=(1-x_1)v$ giving a precise explicit description of all its solutions in $K[F]$. This is important since to any group relation between $x_0$, $x_1$ in $F$ one can naturally assign such a solution. So this can help to estimate the number of relations of a given length between generators.

【69】 Local and Global Convergence of General Burer-Monteiro Tensor Optimizations
标题:广义布里-蒙泰罗张量优化问题的局部收敛性和全局收敛性

链接:https://arxiv.org/abs/2201.02298
作者:Shuang Li,Qiuwei Li
摘要:Tensor optimization is crucial to massive machine learning and signal processing tasks. In this paper, we consider tensor optimization with a convex and well-conditioned objective function and reformulate it into a nonconvex optimization using the Burer-Monteiro type parameterization. We analyze the local convergence of applying vanilla gradient descent to the factored formulation and establish a local regularity condition under mild assumptions. We also provide a linear convergence analysis of the gradient descent algorithm started in a neighborhood of the true tensor factors. Complementary to the local analysis, this work also characterizes the global geometry of the best rank-one tensor approximation problem and demonstrates that for orthogonally decomposable tensors the problem has no spurious local minima and all saddle points are strict except for the one at zero which is a third-order saddle point.

【70】 Delay Alignment Modulation: Enabling Equalization-Free Single-Carrier Communication

链接:https://arxiv.org/abs/2201.02291
作者:Haiquan Lu,Yong Zeng
备注:5 pages, 6 figures
摘要:This paper proposes a novel broadband transmission technology, termed delay alignment modulation (DAM), which enables the low-complexity equalization-free single-carrier communication, yet without suffering from inter-symbol interference (ISI). The key idea of DAM is to deliberately introduce appropriate delays for information-bearing symbols at the transmitter side, so that after propagating over the time-dispersive channel, all multi-path signal components will arrive at the receiver simultaneously and constructively. We first show that by applying DAM for the basic multiple-input single-output (MISO) communication system, an ISI-free additive white Gaussian noise (AWGN) system can be obtained with the simple zero-forcing (ZF) beamforming. Furthermore, the more general DAM scheme is studied with the ISI-maximal-ratio transmission (MRT) and the ISI-minimum mean-square error (MMSE) beamforming. Simulation results are provided to show that when the channel is sparse and/or the antenna dimension is large, DAM not only resolves the notorious practical issues suffered by orthogonal frequency-division multiplexing (OFDM) such as high peak-to-average-power ratio (PAPR), severe out-of-band (OOB) emission, and vulnerability to carrier frequency offset (CFO), with low complexity, but also achieves higher spectral efficiency due to the saving of guard interval overhead.

【71】 Perfect bases in representation theory: three mountains and their springs
标题:表征理论的完美基础:三座山及其泉水

链接:https://arxiv.org/abs/2201.02289
作者:Joel Kamnitzer
备注:18 pages, ICM 2022 proceedings
摘要:In order to give a combinatorial descriptions of tensor product multiplicites for semisimple groups, it is useful to find bases for representations which are compatible with the actions of Chevalley generators of the Lie algebra. There are three known examples of such bases, each of which flows from geometric or algebraic mountain. Remarkably, each mountain gives the same combinatorial shadow: the crystal B(infty) and the Mirkovic-Vilonen polytopes. In order to distinguish between the three bases, we introduce measures supported on these polytopes. We also report on the interaction of these bases with the cluster structure on the coordinate ring of the maximal unipotent subgroup.

【72】 Asymptotic behaviour of non-radiative solution to the wave equations
标题:波动方程非辐射解的渐近行为

链接:https://arxiv.org/abs/2201.02286
作者:Liang Li,Ruipeng Shen,Chenhui Wang,Lijuan Wei
备注:20 pages
摘要:In this work we consider weakly non-radiative solutions to both linear and non-linear wave equations. We first characterize all weakly non-radiative free waves, without the radial assumption. Then in dimension 3 we show that the initial data of non-radiative solutions to a wide range of nonlinear wave equations are similar to those of non-radiative free waves in term of asymptotic behaviour.

【73】 Identities involving the tribonacci numbers squared via tiling with combs
标题:用梳子平铺的包含Tribonacci数平方的恒等式

链接:https://arxiv.org/abs/2201.02285
作者:Michael A. Allen,Kenneth Edwards
备注:7 pages, 1 figure
摘要:The number of ways to tile an $n$-board (an $n\times1$ rectangular board) with $(\frac12,\frac12;1)$-, $(\frac12,\frac12;2)$-, and $(\frac12,\frac12;3)$-combs is $T_{n+2}^2$ where $T_n$ is the $n$th tribonacci number. A $(\frac12,\frac12;m)$-comb is a tile composed of $m$ sub-tiles of dimensions $\frac12\times1$ (with the shorter sides always horizontal) separated by gaps of dimensions $\frac12\times1$. We use such tilings to obtain quick combinatorial proofs of identities relating the tribonacci numbers squared to one another, to other combinations of tribonacci numbers, and to the Fibonacci, Narayana's cows, and Padovan numbers. Most of these identities appear to be new.

【74】 An inequality regarding non-radiative linear waves via a geometric method
标题:关于无辐射线性波的一个几何不等式

链接:https://arxiv.org/abs/2201.02284
作者:Liang Li,Ruipeng Shen,Chenhui Wang
备注:35 pages, 17 figures
摘要:In this work we consider the operator \[ (\mathbf{T} G) (x)= \int_{\mathbb{S}^2} G(x\cdot \omega, \omega) d\omega, \quad x\in \mathbb{R}^3, \; G\in L^2(\mathbb{R}\times \mathbb{S}^2). \] This is the adjoint operator of the Radon transform. We manage to give an optimal $L^6$ decay estimate of $\mathbf{T} G$ near the infinity by a geometric method, if the function $G$ is compactly supported. As an application we give decay estimate of non-radiative solutions to the 3D linear wave equation in the exterior region $\{(x,t)\in \mathbb{R}^3 \times \mathbb{R}: |x|>R+|t|\}$. This kind of decay estimate is useful in the channel of energy method for wave equations

【75】 Long time and large crowd dynamics of discrete Cucker-Smale alignment models
标题:离散Cucker-Smer线形模型的长时间大人群动力学

链接:https://arxiv.org/abs/2201.02281
作者:Eitan Tadmor
摘要:We provide a bird's eye view on developments in analyzing the long time, large crowd behavior of Cucker-Smale alignment dynamics. We consider a class of (fully-)discrete models, paying particular attention to general alignment protocols in which agents, with possibly time-dependent masses, are driven by a large class of heavy-tailed communication kernels. The presence of time-dependent masses allows, in particular, non-symmetric communication. While revisiting known results in the literature, we also shed new light of various aspects on the long time flocking/swarming behavior, driven by the decay of energy fluctuations and heavy-tailed connectivity. We also discuss the large crowd dynamics in terms of the hydrodynamic description of Euler alignment models.

【76】 Regularity and uniqueness results for generated Jacobian equations
标题:生成的Jacobian方程的正则性和唯一性结果

链接:https://arxiv.org/abs/2201.02266
作者:Cale Rankin
备注:ANU PhD thesis
摘要:This is a PhD thesis about generated Jacobian equations; our purpose is twofold. First, we provide an introduction to these equations, whilst, at the same time, collating some results scattered throughout the literature. The other goal is to present the author's own results on these equations. These results all concern solutions of generated Jacobian equations, usually paired with the second boundary value problem. We prove strict convexity and $C^1$ differentiability results under optimal hypothesis in two dimensions, and the same results in higher dimensions with some additional hypothesis. We also consider uniqueness results for the second boundary value problem, and the application of the uniqueness results to global regularity. We conclude with notes on the parabolic generated Jacobian equation. The arXiv version contains minor updates to the ANU open research repository version which is available from the listed DOI.

【77】 The Stability of Generalized Ricci Solitons
标题:广义Ricci孤子的稳定性

链接:https://arxiv.org/abs/2201.02264
作者:Kuan-Hui Lee
摘要:In this paper, I compute the second variation formula of the generalized Einstein-Hilbert functional and prove that a Bismut-flat, Einstein manifold is linearly stable under some curvature assumption. In the last part of the paper, I prove that dynamical stability and the linear stability are equivalent on a steady gradient generalized Ricci soliton $(g,H,f)$ which generalizes the result done by Kr\"oncke, Haslhofer, Sesum, Raffero and Vezzoni.

【78】 Magnetic trajectories on 2-step nilmanifolds
标题:二阶零流形上的磁迹

链接:https://arxiv.org/abs/2201.02258
作者:Gabriela P. Ovando,Mauro Subils
摘要:The aim of this work is the study of magnetic trajectories on nilmanifolds but also of the associated magnetic fields. The magnetic equation is written and the corresponding solutions are found for a family of Lorentz forces. The existence question of magnetic fields is analyzed, obtaining non-existence results. This is extended to prove the non-existence of uniform magnetic fields under certain hypotheses. Finally some examples are computed in the Heisenberg Lie groups $H_n$ for $n=3,5$, showing differences with the case of exact forms. Interesting magnetic trajectories related to elliptic integrals appear in $H_3$. The question of existence of closed or periodic magnetic trajectories for every energy level on Lie groups or on compact quotients is treated.

【79】 Efficient Algebraic Two-Level Schwarz Preconditioner For Sparse Matrices
标题:稀疏矩阵的高效代数两级Schwarz预处理器

链接:https://arxiv.org/abs/2201.02250
作者:Hussam Al Daas,Pierre Jolivet,Tyrone Rees
摘要:Domain decomposition methods are among the most efficient for solving sparse linear systems of equations. Their effectiveness relies on a judiciously chosen coarse space. Originally introduced and theoretically proved to be efficient for self-adjoint operators, spectral coarse spaces have been proposed in the past few years for indefinite and non-self-adjoint operators. This paper presents a new spectral coarse space that can be constructed in a fully-algebraic way unlike most existing spectral coarse spaces. We present theoretical convergence result for Hermitian positive definite diagonally dominant matrices. Numerical experiments and comparisons against state-of-the-art preconditioners in the multigrid community show that the resulting two-level Schwarz preconditioner is efficient especially for non-self-adjoint operators. Furthermore, in this case, our proposed preconditioner outperforms state-of-the-art preconditioners.

【80】 On Spectrum of Nonlinear Continuous Operators
标题:关于非线性连续算子的谱

链接:https://arxiv.org/abs/2201.02245
作者:Kamal N. Soltanov
备注:22 p
摘要:This article proposed a new approach to the determination of the spectrum for nonlinear continuous operators in the Banach spaces and using it investigated the spectrum of some classes of operators. Here shows that in nonlinear operators case is necessary to seek the spectrum of a given nonlinear operator relatively to another nonlinear operator. Moreover, the order of nonlinearity of examined operator and operator relatively to which seek the spectrum must be identical. Here provided different examples relative to how one can find the eigenvalue and also studied solvability problems.

【81】 A proof of the Graham Sloane conjecture
标题:格雷厄姆·斯隆猜想的一个证明

链接:https://arxiv.org/abs/2201.02240
作者:Edinah K. Gnang,Michael Peretzian Williams
备注:arXiv admin note: text overlap with arXiv:2111.12812
摘要:We settle in the affirmative the Graham-Sloane conjecture.

【82】 Torsion and torsion-free classes from objects of finite type in Grothendieck categories
标题:Grothendieck范畴中有限型对象的挠类和无挠类

链接:https://arxiv.org/abs/2201.02224
作者:Daniel Bravo,Sinem Odabaşı,Carlos E. Parra,Marco A. Pérez
备注:27 pages
摘要:In an arbitrary Grothendieck category, we find necessary and sufficient conditions for the class of $\text{FP}_n$-injective objects to be a torsion class. By doing so, we propose a notion of $n$-hereditary categories. We also define and study the class of $\text{FP}_n$-flat objects in Grothendieck categories with a generating set of small projective objects, and provide several equivalent conditions for this class to be torsion-free. In the end, we present several applications and examples of $n$-hereditary categories in the contexts modules over a ring, chain complexes of modules and categories of additive functors from an additive category to the category of abelian groups. Concerning the latter setting, we find a characterization of when these functor categories are $n$-hereditary in terms of the domain additive category.

【83】 Exploring the Steiner-Soddy Porism
标题:斯泰纳-索迪流浪主义探微

链接:https://arxiv.org/abs/2201.02222
作者:Ronaldo Garcia,Liliana Gheorghe,Dan Reznik
备注:12 pages, 6 figures, 1 table
摘要:We explore properties and loci of a Poncelet family of polygons -- called here Steiner-Soddy -- whose vertices are centers of circles in the Steiner porism, including conserved quantities, loci, and its relationship to other Poncelet families.

【84】 Almost order-weakly compact operators on Banach lattices
标题:Banach格上的几乎序弱紧算子

链接:https://arxiv.org/abs/2201.02219
作者:Mina Matin,Mina Matin,Kazem Haghnejad Azar,Ali Ebadi
摘要:A continuous operator $T$ between two Banach lattices $E$ and $F$ is called almost order-weakly compact, whenever for each almost order bounded subset $A$ of $E$, $T(A)$ is a relatively weakly compact subset of $F$. In Theorem 4, we show that the positive operator $T$ from $E$ into Dedekind complete $F$ is almost order-weakly compact if and only if $T(x_n) \xrightarrow{\|.\|}0$ in $F$ for each disjoint almost order bounded sequence $\{x_n\}$ in $E$. In this manuscript, we study some properties of this class of operators and its relationships with others known operators.

【85】 Isoperimetric 3- and 4-bubble results on $\mathbb{R}$ with density $|x|$

链接:https://arxiv.org/abs/2201.02197
作者:Evan Alexander,Emily Burns,John Ross,Jesse Stovall,Zariah Whyte
备注:1 figure. arXiv admin note: text overlap with arXiv:2201.01808
摘要:We study the isoperimetric problem on $\mathbb{R}^1$ with a prescribed density function $f(x) = |x|$. Under these conditions, we find that isoperimetric $3$-bubble and $4$-bubble results satisfy a regular structure. As our regions increase in size, the intervals that form them alternate back-and-forth across the origin, with the smaller regions closer to the origin. This expands on previously known observations about the single- and double-bubble results on $\mathbb{R}$ with density $|x|^p$.

【86】 Pricing Bermudan options using regression trees/random forests
标题:使用回归树/随机森林为百慕大期权定价

链接:https://arxiv.org/abs/2201.02587
作者:Zineb El Filali Ech-Chafiq,Pierre Henry-Labordere,Jérôme Lelong
摘要:The value of an American option is the maximized value of the discounted cash flows from the option. At each time step, one needs to compare the immediate exercise value with the continuation value and decide to exercise as soon as the exercise value is strictly greater than the continuation value. We can formulate this problem as a dynamic programming equation, where the main difficulty comes from the computation of the conditional expectations representing the continuation values at each time step. In (Longstaff and Schwartz, 2001), these conditional expectations were estimated using regressions on a finite-dimensional vector space (typically a polynomial basis). In this paper, we follow the same algorithm; only the conditional expectations are estimated using Regression trees or Random forests. We discuss the convergence of the LS algorithm when the standard least squares regression is replaced with regression trees. Finally, we expose some numerical results with regression trees and random forests. The random forest algorithm gives excellent results in high dimensions.

【87】 Quantifying unsharpness of observables in an outcome-independent way

链接:https://arxiv.org/abs/2201.02578
作者:Arindam Mitra
备注:11 pages, 2 figures
摘要:Recently a very beautiful measure of the unsharpness (fuzziness) of the observables is discussed in the paper [Phys. Rev. A 104, 052227 (2021)]. The measure which is defined in this paper is constructed via uncertainty and does not depend on the values of the outcomes. There exist several properties of a set of observables (e.g., incompatibility, non-disturbance) that do not depend on the values of the outcomes. Therefore, the approach in the above-said paper is consistent with the above-mentioned fact and is able to measure the intrinsic unsharpness of the observables. In this work, we also quantify the unsharpness of observables in an outcome-independent way. But our approach is different than the approach of the above-said paper. In this work, at first, we construct a Luder's instrument-based unsharpness measure and provide a tight upper bound of that measure. Then we prove the monotonicity of the above-said measure under a class of fuzzifying processes (processes that make the observables more fuzzy). This is consistent with the resource-theoretic framework. Then we relate our approach to the approach of the above-said paper. Next, we try to construct an instrument-independent unsharpness measure. In particular, we define an instrument-independent unsharpness measure and provide a tight upper bound of that measure and then we derive the condition for the monotonicity of the measure under a class of fuzzifying processes and prove the monotonicity for dichotomic qubit observables. Then we show that for an unknown measurement, the value of these measures can be determined experimentally. Finally, we present the idea of the resource theory of the sharpness of the observables.

【88】 The spatial Functional Renormalization Group and Hadamard states on cosmological spacetimes

链接:https://arxiv.org/abs/2201.02575
作者:Rudrajit Banerjee,Max Niedermaier
备注:59 pages, 1 figure
摘要:A spatial variant of the Functional Renormalization Group (FRG) is introduced on (Lorentzian signature) globally hyperbolic spacetimes. Through its perturbative expansion it is argued that such a FRG must inevitably be state dependent and that it should be based on a Hadamard state. A concrete implementation is presented for scalar quantum fields on flat Friedmann-Lema\^{i}tre spacetimes. The universal ultraviolet behavior of Hadamard states allows the flow to be matched to the one-loop renormalized flow (where strict removal of the ultraviolet cutoff requires a tower of potentials, one for each power of the Ricci scalar). The state-dependent infrared behavior of the flow is investigated for States of Low Energy, which are Hadamard states deemed to be viable vacua for a pre-inflationary period. A simple time-dependent infrared fixed point equation (resembling that in Minkowski space) arises for any scale factor, with analytically computable corrections coding the non-perturbative ramifications of the Hadamard property in the infrared.

【89】 Rethinking the ill-posedness of the spectral function reconstruction -- why is it fundamentally hard and how Artificial Neural Networks can help

链接:https://arxiv.org/abs/2201.02564
作者:Shuzhe Shi,Lingxiao Wang,Kai Zhou
备注:29 pages, 6 figures
摘要:Reconstructing hadron spectral functions through Euclidean correlation functions are of the important missions in lattice QCD calculations. However, in a K\"allen--Lehmann(KL) spectral representation, the reconstruction is observed to be ill-posed in practice. It is usually ascribed to the fewer observation points compared to the number of points in the spectral function. In this paper, by solving the eigenvalue problem of continuous KL convolution, we show analytically that the ill-posedness of the inversion is fundamental and it exists even for continuous correlation functions. We discussed how to introduce regulators to alleviate the predicament, in which include the Artificial Neural Networks(ANNs) representations recently proposed by the Authors in [arXiv:2111.14760]. The uniqueness of solutions using ANNs representations is manifested analytically and validated numerically. Reconstructed spectral functions using different regularization schemes are also demonstrated, together with their eigen-mode decomposition. We observe that components with large eigenvalues can be reliably reconstructed by all methods, whereas those with low eigenvalues need to be constrained by regulators.

【90】 Solving formally the Auxiliary System of $O(N)$ Non Linear Sigma Model

链接:https://arxiv.org/abs/2201.02493
作者:Dimitrios Katsinis
备注:5 pages
摘要:We show that the integrability of the $SO(N)/SO(N-1)$ Principal Chiral Model (PCM) originates from the Pohlmeyer reduction of the $O(N)$ Non Linear Sigma Model (NLSM). In particular, we show that the Lax pair of the PCM is related upon redefinitions and identification of parameters to the zero curvature condition, which is a consequence of the flatness of the enhanced space used in the Pohlmeyer reduction. This identification provides the solution of the auxiliary system that corresponds to an arbitrary NLSM/PCM solution.

【91】 Sparse PCA on fixed-rank matrices
标题:固定秩矩阵上的稀疏PCA

链接:https://arxiv.org/abs/2201.02487
作者:Alberto Del Pia
备注:None
摘要:Sparse PCA is the optimization problem obtained from PCA by adding a sparsity constraint on the principal components. Sparse PCA is NP-hard and hard to approximate even in the single-component case. In this paper we settle the computational complexity of sparse PCA with respect to the rank of the covariance matrix. We show that, if the rank of the covariance matrix is a fixed value, then there is an algorithm that solves sparse PCA to global optimality, whose running time is polynomial in the number of features. We also prove a similar result for the version of sparse PCA which requires the principal components to have disjoint supports.

【92】 Power and Sample Size Calculations for Rerandomized Experiments
标题:随机试验的功率和样本量计算

链接:https://arxiv.org/abs/2201.02486
作者:Zach Branson,Xinran Li,Peng Ding
备注:20 pages, 4 figures
摘要:Power is an important aspect of experimental design, because it allows researchers to understand the chance of detecting causal effects if they exist. It is common to specify a desired level of power, and then compute the sample size necessary to obtain that level of power; thus, power calculations help determine how experiments are conducted in practice. Power and sample size calculations are readily available for completely randomized experiments; however, there can be many benefits to using other experimental designs. For example, in recent years it has been established that rerandomized designs, where subjects are randomized until a prespecified level of covariate balance is obtained, increase the precision of causal effect estimators. This work establishes the statistical power of rerandomized treatment-control experiments, thereby allowing for sample size calculators. Our theoretical results also clarify how power and sample size are affected by treatment effect heterogeneity, a quantity that is often ignored in power analyses. Via simulation, we confirm our theoretical results and find that rerandomization can lead to substantial sample size reductions; e.g., in many realistic scenarios, rerandomization can lead to a 25% or even 50% reduction in sample size for a fixed level of power, compared to complete randomization. Power and sample size calculators based on our results are in the R package rerandPower on CRAN.

【93】 Polynomial Dynamical Systems and Differentiation of Genus 4 Hyperelliptic Functions
标题:多项式动力系统与亏格4的超椭圆函数的微分

链接:https://arxiv.org/abs/2201.02462
作者:E. Yu. Bunkova
摘要:We give an explicit solution to the problem of differentiation of hyperelliptic functions in genus 4 case. We describe explicitly the polynomial Lie algebras and polynomial dynamical systems connected to this problem.

【94】 General rogue wave solutions to the discrete nonlinear Schrödinger equation

链接:https://arxiv.org/abs/2201.02359
作者:Yasuhiro Ohta,Bao-Feng Feng
备注:16 pages, 4 figures
摘要:In the present paper, we attempt to construct both the general rogue wave solutions to the fully discrete nonlinear Schr\"odinger (fd-NLS) equation via the KP-Toda reduction method. First, we deduce the general breather solution of the fd-NLS equation starting from a pair of bilinear equations. We then derive the general rogue wave solution by taking a limit to the breather solution.

【95】 Persistent Homology for Breast Tumor Classification using Mammogram Scans
标题:使用乳腺X线扫描实现乳腺肿瘤分类的持久同源性

链接:https://arxiv.org/abs/2201.02295
作者:Aras Asaad,Dashti Ali,Taban Majeed,Rasber Rashid
备注:10 pages
摘要:An Important tool in the field topological data analysis is known as persistent Homology (PH) which is used to encode abstract representation of the homology of data at different resolutions in the form of persistence diagram (PD). In this work we build more than one PD representation of a single image based on a landmark selection method, known as local binary patterns, that encode different types of local textures from images. We employed different PD vectorizations using persistence landscapes, persistence images, persistence binning (Betti Curve) and statistics. We tested the effectiveness of proposed landmark based PH on two publicly available breast abnormality detection datasets using mammogram scans. Sensitivity of landmark based PH obtained is over 90% in both datasets for the detection of abnormal breast scans. Finally, experimental results give new insights on using different types of PD vectorizations which help in utilising PH in conjunction with machine learning classifiers.

【96】 Well-Conditioned Linear Minimum Mean Square Error Estimation

链接:https://arxiv.org/abs/2201.02275
作者:Edwin K. P. Chong
摘要:Computing linear minimum mean square error (LMMSE) filters is often ill conditioned, suggesting that unconstrained minimization of the mean square error is an inadequate principle for filter design. To address this, we first develop a unifying framework for studying constrained LMMSE estimation problems. Using this framework, we expose an important structural property of all constrained LMMSE filters and show that they all involve an inherent preconditioning step. This parameterizes all such filters only by their preconditioners. Moreover, each filters is invariant to invertible linear transformations of its preconditioner. We then clarify that merely constraining the rank of the filters, leading to the well-known low-rank Wiener filter, does not suitably address the problem of ill conditioning. Instead, we use a constraint that explicitly requires solutions to be well conditioned in a certain specific sense. We introduce two well-conditioned estimators and evaluate their mean-squared-error performance. We show these two estimators converge to the standard LMMSE filter as their truncated-power ratio converges to zero, but more slowly than the low-rank Wiener filter in terms of scaling law. This exposes the price for being well conditioned. We also show quantitative results with historical VIX data to illustrate the performance of our two well-conditioned estimators.

【97】 Schwarzian derivative, Painlevé XXV-Ermakov equation and Bäcklund transformations

链接:https://arxiv.org/abs/2201.02267
作者:Sandra Carillo,Alexander Chichurin,Galina Filipuk,Federico Zullo
备注:21 pages
摘要:The role of Schwarzian derivative in the study of nonlinear ordinary differential equations is revisited. Solutions and invariances admitted by Painlev\'e XXV-Ermakov equation, Ermakov equation and third order linear equation in a normal form are shown to be based on solutions of the Schwarzian equation. Starting from the Riccati equation and the second order element of the Riccati chian as the simplest examples of linearizable equations, by introducing a suitable change of variables, it is shown how the Schwarzian derivative represents a key tool in the construction of solutions. Two families of B\"acklund transformations which link the linear and nonlinear equations under investigation are obtained. Some examples with relevant applications are given and discussed.

【98】 Invasion of cooperative parasites in moderately structured host populations
标题:合作寄生虫在中等结构宿主群体中的入侵

链接:https://arxiv.org/abs/2201.02249
作者:Vianney Brouard,Cornelia Pokalyuk
摘要:Certain defense mechanisms of phages against the immune system of their bacterial host rely on cooperation of phages. Motivated by this example we analyse invasion probabilities of cooperative parasites in host populations that are moderately structured. More precisely we assume that hosts are arranged on the vertices of a configuration model and that offspring of parasites move to nearest neighbours sites to infect new hosts. We consider parasites that generate many offspring at reproduction, but do this (usually) only when infecting a host simultaneously. In this regime we identify and analyse the spatial scale of the population structure at which invasion of parasites turns from being an unlikely to an highly probable event.

【99】 Quantum computing based on complex Clifford algebras

链接:https://arxiv.org/abs/2201.02246
作者:Jaroslav Hrdina,Ales Navrat,Petr Vasik
摘要:We propose to represent both $n$--qubits and quantum gates acting on them as elements in the complex Clifford algebra defined on a complex vector space of dimension $2n.$ We demonstrate its functionality by performing quantum computations with several well known examples of quantum gates. We also compare our approach with representations that use real geometric algebras.

【100】 An Input-to-State Safety Approach to Anomaly-Resilient Parabolic PDEs: Application to Cyber-Physical Battery Modules
标题:异常弹性抛物型偏微分方程的输入到状态安全方法:在网络物理电池模块中的应用

链接:https://arxiv.org/abs/2201.02239
作者:Tanushree Roy,Ashley Knichel,Satadru Dey
摘要:Distributed Parameter Cyber-Physical Systems (DPCPSs), modelled by Partial Differential Equations (PDEs), are increasingly vulnerable to anomalies such as physical faults as well as cyber-attacks. This motivates the need for strategies towards anomaly-resilient control of these systems. Although anomaly detection and diagnostics in PDE systems have received considerable attention in existing literature, fault-tolerant or anomaly-resilient control for PDEs remains relatively under-explored. However, given the vulnerabilities of these systems against anomalies, it is essential that the control systems possess resilience against these disruptions. In this context, we explore a Practical Input-to-Safety (pISSf) based control design approach for a class of DPCPSs modelled by linear Parabolic PDEs. Specifically, we develop a design framework for anomaly-resilient control for this class of system with both safety and stability guarantees based on control Lyapunov functional and control barrier functional. To illustrate our methodology, we apply our strategy to design a thermal-anomaly resilient boundary coolant control system for a cyber-physical battery module. Several simulation studies are done to show the efficacy of our method under anomalies such as mechanical battery degradation and cyber-attack mediated overdischarge.

【101】 Persistent oscillations after quantum quenches in $d$ dimensions

链接:https://arxiv.org/abs/2107.13240
作者:Gesualdo Delfino,Marianna Sorba
备注:None
摘要:We obtain analytical results for the time evolution of local observables in systems undergoing quantum quenches in $d$ spatial dimensions. For homogeneous systems we show that oscillations undamped in time occur when the state produced by the quench includes single-quasiparticle modes and the observable couples to those modes. In particular, a quench of the transverse field within the ferromagnetic phase of the Ising model produces undamped oscillations of the order parameter when $d>1$. For the more general case in which the quench is performed only in a subregion of the whole $d$-dimensional space occupied by the system, the time evolution occurs inside a light cone spreading away from the boundary of the quenched region as time increases. The additional condition for undamped oscillations is that the volume of the quenched region is extensive in all dimensions.

【102】 Stream/block ciphers, difference equations and algebraic attacks
标题:流/挡路密码、差分方程和代数攻击

链接:https://arxiv.org/abs/2003.14215
作者:Roberto La Scala,Sharwan K. Tiwari
备注:26 pages, to appear in Journal of Symbolic Computation
摘要:In this paper we model a class of stream and block ciphers as systems of (ordinary) explicit difference equations over a finite field. We call this class "difference ciphers" and we show that ciphers of application interest, as for example systems of LFSRs with a combiner, Trivium and Keeloq, belong to the class. By using Difference Algebra, that is, the formal theory of difference equations, we can properly define and study important properties of these ciphers, such as their invertibility and periodicity. We describe then general cryptanalytic methods for difference ciphers that follow from these properties and are useful to assess the security. We illustrate such algebraic attacks in practice by means of the ciphers Bivium and Keeloq.

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