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Related papers: On weak cop numbers of transitive graphs

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We study the reverse mathematics and computability of countable graph theory, obtaining the following results. The principle that every countable graph has a connected component is equivalent to $\mathsf{ACA}_0$ over $\mathsf{RCA}_0$. The…

Logic · Mathematics 2015-08-27 Kirill Gura , Jeffry L. Hirst , Carl Mummert

It is shown that there are infinitely many connected vertex-transitive graphs that have no Hamilton decomposition, including infinitely many Cayley graphs of valency 6, and including Cayley graphs of arbitrarily large valency.

Combinatorics · Mathematics 2014-11-13 Darryn Bryant , Matthew Dean

We prove that a simple random walk on quasi-transitive graphs with the volume growth being faster than any polynomial of degree 4 has a.s. infinitely many cut times, and hence infinitely many cutpoints. This confirms a conjecture raised by…

Probability · Mathematics 2017-12-08 He Song , Kainan Xiang

This paper describes a 720-vertex connected planar graph G such that cop1(G), denoting the minimum number of cops needed to catch the robber in the 1-cop-move game on G, is at least 4 and at most 7. Furthermore, G has a connected subgraph H…

Discrete Mathematics · Computer Science 2019-12-17 Wei Quan Lim

The vertex cover number of a graph is the minimum number of vertices that are needed to cover all edges. When those vertices are further required to induce a connected subgraph, the corresponding number is called the connected vertex cover…

Discrete Mathematics · Computer Science 2013-05-16 Eglantine Camby , Jean Cardinal , Samuel Fiorini , Oliver Schaudt

The cop number of a graph $G$ is the smallest $k$ such that $k$ cops win the game of cops and robber on $G$. We investigate the maximum cop number of geometric intersection graphs, which are graphs whose vertices are represented by…

We consider the lattice of all the weak factorization systems on a given finite lattice. We prove that it is semidistributive, trim and congruence uniform. We deduce a graph theoretical approach to the problem of enumerating transfer…

Combinatorics · Mathematics 2024-10-10 Yongle Luo , Baptiste Rognerud

A core of a graph X is a vertex minimal subgraph to which X admits a homomorphism. Hahn and Tardif have shown that for vertex transitive graphs, the size of the core must divide the size of the graph. This motivates the following question:…

Combinatorics · Mathematics 2013-02-20 David Roberson

The theory of graph limits represents large graphs by analytic objects called graphons. Graph limits determined by finitely many graph densities, which are represented by finitely forcible graphons, arise in various scenarios, particularly…

Combinatorics · Mathematics 2018-10-10 Jacob W. Cooper , Daniel Kral , Taisa L. Martins

The \textit{$k$-weak-dynamic number} of a graph $G$ is the smallest number of colors we need to color the vertices of $G$ in such a way that each vertex $v$ of degree $d(v)$ sees at least $\rm{min}\{k,d(v)\}$ colors on its neighborhood. We…

Combinatorics · Mathematics 2018-02-19 Caroline Accurso , Vitaliy Chernyshov , Leaha Hand , Sogol Jahanbekam , Paul Wenger

This paper presents an exhaustive approach for verification of the weak reconstruction of Self Complementary Graphs up to 17 vertices. It describes the general problem of the Reconstruction Conjecture, explaining the complexity involved in…

Discrete Mathematics · Computer Science 2010-12-30 S. K. Gupta , Sahil Singla , Akash Khandelwal , Apurv Tiwari , Srilekha

An identifying code of a graph G is a dominating set C such that every vertex x of G is distinguished from all other vertices by the set of vertices in C that are at distance at most 1 from x. The problem of finding an identifying code of…

Discrete Mathematics · Computer Science 2011-02-25 Florent Foucaud , Eleonora Guerrini , Matjaz Kovse , Reza Naserasr , Aline Parreau , Petru Valicov

Let $G$ and $H$ be disjoint embeddings of complete graphs $K_m$ and $K_n$ in $\mathbb{R}^3$ such that some cycle in $G$ links a cycle in $H$ with non-zero linking number. We say that $G$ and $H$ are *weakly linked* if the absolute value of…

Geometric Topology · Mathematics 2024-07-23 James Di , Erica Flapan , Spencer Johnson , Daniel Thompson , Christopher Tuffley

A graph is called {\em arc-transitive} (or {\em symmetric}) if its automorphism group has a single orbit on ordered pairs of adjacent vertices, and 2-arc-transitive its automorphism group has a single orbit on ordered paths of length 2. In…

Group Theory · Mathematics 2014-09-30 Marston D. E. Conder , Cai-Heng Li , Primoz Potocnik

We consider a variant of the Cops and Robbers game where the robber can move t edges at a time, and show that in this variant, the cop number of a d-regular graph with girth larger than 2t+2 is Omega(d^t). By the known upper bounds on the…

Combinatorics · Mathematics 2011-06-03 Abbas Mehrabian

Cops and Robbers is a well-studied pursuit-evasion game in which a set of cops seeks to catch a robber in a graph G, where cops and robber move along edges of G. The cop number of G is the minimum number of cops that is sufficient to catch…

In this short paper we study the game of cops and robbers, which is played on the vertices of some fixed graph $G$. Cops and a robber are allowed to move along the edges of $G$ and the goal of cops is to capture the robber. The cop number…

Combinatorics · Mathematics 2010-04-13 Alex Scott , Benny Sudakov

Cops and robbers is a turn-based pursuit game played on a graph $G$. One robber is pursued by a set of cops. In each round, these agents move between vertices along the edges of the graph. The cop number $c(G)$ denotes the minimum number of…

Combinatorics · Mathematics 2011-09-09 Andrew Beveridge , Andrzej Dudek , Alan Frieze , Tobias Müller

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

Richter and Thomassen proved that every graph has an edge $e$ such that the crossing number $\ucr(G-e)$ of $G-e$ is at least $(2/5)\ucr(G) - O(1)$. Fox and Cs. T\'oth proved that dense graphs have large sets of edges (proportional in the…

Combinatorics · Mathematics 2012-03-05 Jozsef Balogh , Jesus Leanos , Gelasio Salazar
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