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Isoradial graphs are a natural generalization of regular graphs which give, for many models of statistical mechanics, the right framework for studying models at criticality. In this survey paper, we first explain how isoradial graphs…

Probability · Mathematics 2010-12-16 Cédric Boutillier , Béatrice De Tilière

H. Furstenberg defined Central sets in $\mathbb{N}$ by using the notions of topological dynamics, later Bergelson and Hindman characterized central sets in $\mathbb{N}$ and also in arbitrary semigroup in terms of algebra of Stone-\v{C}ech…

Combinatorics · Mathematics 2024-06-10 H. Goodarzi , M. A. Tootkaboni , Arpita Ghosh

A graph is said to be {\em vertex-transitive non-Cayley} if its full automorphism group acts transitively on its vertices and contains no subgroups acting regularly on its vertices. In this paper, a complete classification of cubic…

Combinatorics · Mathematics 2017-05-15 Wei-Juan Zhang , Yan-Quan Feng , Jin-Xin Zhou

We exactly settle the complexity of graph realization, graph rigidity, and graph global rigidity as applied to three types of graphs: "globally noncrossing" graphs, which avoid crossings in all of their configurations; matchstick graphs,…

Computational Geometry · Computer Science 2025-10-21 Zachary Abel , Erik D. Demaine , Martin L. Demaine , Sarah Eisenstat , Jayson Lynch , Tao B. Schardl

We introduce a new class of identifiable DAG models where the conditional distribution of each node given its parents belongs to a family of generalized hypergeometric distributions (GHD). A family of generalized hypergeometric…

Machine Learning · Statistics 2019-10-17 Gunwoong Park , Hyewon Park

Mixed graphs can be seen as digraphs that have both arcs and edges (or digons, that is, two opposite arcs). In this paper, we consider the case in which such graphs are Cayley graphs of Abelian groups. These groups can be constructed by…

Combinatorics · Mathematics 2020-05-20 C. Dalfó , M. A. Fiol , N. López

We give a way to construct group of pseudo-automorphisms of rational varieties of any dimension that fix pointwise the image of a cubic hypersurface of $P^n. These group are free products of involutions, and most of their elements have…

Dynamical Systems · Mathematics 2014-05-14 Jérémy Blanc

A subgroup of the automorphism group of a graph acts {\em half-arc-transitively} on the graph if it acts transitively on the vertex-set and on the edge-set of the graph but not on the arc-set of the graph. If the full automorphism group of…

Combinatorics · Mathematics 2024-12-09 Štefko Miklavič , Primož Šparl , Stephen E. Wilson

One exact and two heuristic algorithms for determining the generators, orbits and order of the graph automorphism group are presented. A basic tool of these algorithms is the well-known individualization and refinement procedure. A search…

Data Structures and Algorithms · Computer Science 2016-07-27 Stoicho D. Stoichev

Sandpile groups are a subtle graph isomorphism invariant, in the form of a finite abelian group, whose cardinality is the number of spanning trees in the graph. We study their group structure for graphs obtained by attaching a cone vertex…

Combinatorics · Mathematics 2024-09-04 Victor Reiner , Dorian Smith

Recently, a new way of avoiding crossings in straight-line drawings of non-planar graphs has been investigated. The idea of partial edge drawings (PED) is to drop the middle part of edges and rely on the remaining edge parts called stubs.…

Simple drawings are drawings of graphs in which any two edges intersect at most once (either at a common endpoint or a proper crossing), and no edge intersects itself. We analyze several characteristics of simple drawings of complete…

Computational Geometry · Computer Science 2023-08-22 Oswin Aichholzer , Birgit Vogtenhuber , Alexandra Weinberger

In analogy with epsilon-biased sets over Z_2^n, we construct explicit epsilon-biased sets over nonabelian finite groups G. That is, we find sets S subset G such that | Exp_{x in S} rho(x)| <= epsilon for any nontrivial irreducible…

Computational Complexity · Computer Science 2013-05-01 Sixia Chen , Cristopher Moore , Alexander Russell

Graph signal processing (GSP) provides a powerful framework for analyzing signals arising in a variety of domains. In many applications of GSP, multiple network structures are available, each of which captures different aspects of the same…

Machine Learning · Statistics 2021-11-03 Michael Weylandt , George Michailidis , T. Mitchell Roddenberry

This article is a review of theoretical advances in the research field of algebraic geometry and Bayesian statistics in the last two decades. Many statistical models and learning machines which contain hierarchical structures or latent…

Statistics Theory · Mathematics 2022-11-21 Sumio Watanabe

Recently, there has been interest in the question of whether a partial matrix in which many of the fully defined principal submatrices are PSD is approximately PSD completable. These questions are related to graph theory because we can…

Optimization and Control · Mathematics 2021-07-27 Kevin Shu

We present an algebraic procedure for constructing Hamiltonians with several distinct partial dynamical symmetries (PDSs), of relevance to shape-coexistence phenomena. The procedure relies on a spectrum generating algebra encompassing…

Nuclear Theory · Physics 2018-09-11 A Leviatan , N Gavrielov

Given a graph $A$ on a group $G$ and an equivalence relation $B$ on $G$, the $B$ super$A$ graph, whose vertex set is $G$ and two vertices $g$, $h$ are adjacent if and only if there exist $g^{\prime} \in[g]$ and $h^{\prime} \in[h]$ such that…

Combinatorics · Mathematics 2024-11-27 Varun J Kaushik , Ekta , Parveen , Jitender Kumar

A \emph{proportionally dense subgraph} (PDS) is an induced subgraph of a graph with the property that each vertex in the PDS is adjacent to proportionally as many vertices in the subgraph as in the rest of the graph. In this paper, we study…

Discrete Mathematics · Computer Science 2025-01-15 Cristina Bazgan , Janka Chlebíková , Clément Dallard

Strongly walk regular graphs (SWRGs or $s$-SWRGs) form a natural generalization of strongly regular graphs (SRGs) where paths of length~2 are replaced by paths of length~$s$. They can be constructed as coset graphs of the duals of…

Combinatorics · Mathematics 2025-10-02 Michael Kiermaier , Sascha Kurz , Patrick Solé , Michael Stoll , Alfred Wassermann