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Related papers: Semigroups for flows on limits of graphs

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A paradigm that was successfully applied in the study of both pure and algorithmic problems in graph theory can be colloquially summarized as stating that "any graph is close to being the disjoint union of expanders". Our goal in this paper…

Combinatorics · Mathematics 2015-02-03 Guy Moshkovitz , Asaf Shapira

We present the operator semigroups approach to first- and second-order dynamical systems taking place on metric graphs. We briefly survey the existing results and focus on the well-posedness of the problems with standard vertex conditions.…

Analysis of PDEs · Mathematics 2020-09-22 Marjeta Kramar Fijavž , Aleksandra Puchalska

In this work, we study good semigroups of $\mathbb{N}^n$ introducing the definition of length and genus for these objects. We show how to count the local good semigroup with a fixed genus. Furthermore, we study the relationships of these…

Commutative Algebra · Mathematics 2020-06-02 Nicola Maugeri , Giuseppe Zito

We give a number of approximation metatheorems for monotone maximization problems expressible in the first-order logic, in substantially more general settings than the previously known. We obtain * constant-factor approximation algorithm in…

Discrete Mathematics · Computer Science 2021-10-12 Zdeněk Dvořák

We consider infinite connected quasi-transitive locally finite graphs and show that every such graph with more than one end is a tree amalgamation of two other such graphs. This can be seen as a graph-theoretical version of Stallings'…

Combinatorics · Mathematics 2019-06-19 Matthias Hamann , Florian Lehner , Babak Miraftab , Tim Rühmann

We recently introduced a formalism for the modeling of temporal networks, that we call stream graphs. It emphasizes the streaming nature of data and allows rigorous definitions of many important concepts generalizing classical graphs. This…

Social and Information Networks · Computer Science 2021-11-24 Matthieu Latapy , Clémence Magnien , Tiphaine Viard

We use semigroup theory to describe the group of automorphisms of some semigroups of interest in holomorphic dynamical systems. We show, with some examples, that representation theory of semigroups is related to usual constructions in…

Dynamical Systems · Mathematics 2010-09-16 Carlos Cabrera , Peter Makienko , Peter Plaumann

We prove an approximate spectral theorem for non-self-adjoint operators and investigate its applications to second order differential operators in the semi-classical limit. This leads to the construction of a twisted FBI transform. We also…

Spectral Theory · Mathematics 2007-05-23 E. B. Davies

We refine the construction of quasi-homomorphisms on mapping class groups. It is useful to know that there are unbounded quasi-homomorphisms which are bounded when restricted to particular subgroups since then one deduces that the mapping…

Group Theory · Mathematics 2007-05-23 Mladen Bestvina , Koji Fujiwara

Directed graphs have long been used to gain understanding of the structure of semigroups, and recently the structure of directed graph semigroups has been investigated resulting in a characterization theorem and an analog of Fruct's…

Combinatorics · Mathematics 2015-06-09 Tien Chih , Demitri Plessas

We combine Gromov's amenable localization technique with the Poincar\'{e} duality to study the traversally generic vector flows on smooth compact manifolds $X$ with boundary. Such flows generate well-understood stratifications of $X$ by the…

Geometric Topology · Mathematics 2015-11-24 Gabriel Katz

We study semigroups of labellings associated to a graph. These generalize the Jukes-Cantor model and phylogenetic toric varieties defined by Buczy\'nska. Our main theorem bounds the degree of the generators of the semigroup by g+1 when the…

Combinatorics · Mathematics 2016-05-19 Weronika Buczyńska , Jarosław Buczyński , Kaie Kubjas , Mateusz Michałek

We give a self-contained and streamlined exposition of a generation theorem for C0-semigroups based on the method of boundary triplets. We apply this theorem to port-Hamiltonian systems where we discuss recent results appearing in stability…

Functional Analysis · Mathematics 2020-05-26 Sven-Ake Wegner

We classify the finite quasisimple groups whose commuting graph is perfect and we give a general structure theorem for finite groups whose commuting graph is perfect.

Group Theory · Mathematics 2015-10-26 John R. Britnell , Nick Gill

We construct p.m.p. group actions that are not local-global limits of sequences of finite graphs. Moreover, they do not weakly contain any sequence of finite labeled graphs. Our methods are based on the study of almost automorphisms of…

Group Theory · Mathematics 2019-01-16 Gabor Kun , Andreas Thom

In this manuscript we review new ideas and first results on application of the Graphical Models approach, originated from Statistical Physics, Information Theory, Computer Science and Machine Learning, to optimization problems of network…

Systems and Control · Computer Science 2017-02-08 Michael Chertkov , Sidhant Misra , Marc Vuffray , Dvijotham Krishnamurty , Pascal Van Hentenryck

We introduce the notion of a generalized flow on a graph with coefficients in a R-representation and show that the module of flows is isomorphic to the first derived functor of the colimit. We generalize Kirchhoff's laws and build an exact…

Category Theory · Mathematics 2023-06-27 A. A. Husainov , H. Calisici

This paper gives a framework to study a continuum limit of a gradient flow on a graph where the number of vertices increases in an appropriate way. As examples we prove the convergence of a discrete total variation flow and a discrete…

Analysis of PDEs · Mathematics 2022-11-08 Yoshikazu Giga , Yves van Gennip , Jun Okamoto

Recent algorithmic advances in algebraic automata theory drew attention to semigroupoids (semicategories). These are mathematical descriptions of typed computational processes, but they have not been studied systematically in the context of…

Formal Languages and Automata Theory · Computer Science 2025-09-30 Attila Egri-Nagy , Chrystopher L. Nehaniv

We classify certain sofic shifts (the irreducible Point Extension Type, or PET, sofic shifts) up to flow equivalence, using invariants of the canonical Fischer cover. There are two main ingredients: (1) An extension theorem, for extending…

Dynamical Systems · Mathematics 2018-10-08 Mike Boyle , Toke Meier Carlsen , Søren Eilers