Results 51 to 60 of about 514 (184)

Chromatic Ramsey Numbers and Two‐Color Turán Densities

Journal of Graph Theory, EarlyView.
ABSTRACT Given a graph G, its 2‐color Turán number ex ( 2 ) ( n , G ) is the maximum number of edges in an n‐vertex graph, such that the edges can be colored with two colors avoiding a monochromatic copy of G. Let π ( 2 ) ( G ) = lim n → ∞ ex ( 2 ) ( n , G ) / n 2 be the 2‐color Turán density of G.
Maria Axenovich, Simon Gaa, Dingyuan Liu
wiley   +1 more source

Explicit 3‐colorings for Exponential Graphs

Journal of Graph Theory, EarlyView.
ABSTRACT In 1985, El‐Zahar and Sauer showed that the chromatic number of the direct product of two 4‐chromatic graphs is 4, establishing a nontrivial case of Hedetniemi's conjecture, which has since been refuted in general. Their proof uses the concept of an exponential graph, showing that if a graph H $H$ has no proper 3‐coloring, then the exponential
Adrien Argento, Pierre Charbit, Alantha Newman   +2 more
wiley   +1 more source

A Framework Similarity Estimation of Unweighted Undirected Graphs

Современные информационные технологии и IT-образование, 2022
It is well known that the problem of algorithms for estimating the similarity of graphs rests on the complexity of their computation. Most proposed algorithms for estimating graph similarity are based on Ullman’s algorithm.
Valentin Sysoev
doaj   +1 more source

Line Graphs of Multigraphs and the Forbidden Graph E 6

Journal of Graph Theory, EarlyView.
ABSTRACT The line graph Γ of a multigraph Δ is the graph whose vertices are the edges of Δ, where two such edges are adjacent if and only if they meet in a single vertex of Δ. We provide several characterizations of such line graphs and in particular show that a graph is a line graph if and only if it does not contain one of the 32 graphs, all of which
Hans Cuypers
wiley   +1 more source

Graph Homomorphisms and Phase Transitions

Journal of Combinatorial Theory, Series B, 1999
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Graham R. Brightwell, Peter Winkler 0001
openaire   +1 more source

Words and polynomial invariants of finite groups in non-commutative variables [PDF]

Discrete Mathematics & Theoretical Computer Science, 2009
Let $V$ be a complex vector space with basis $\{x_1,x_2,\ldots,x_n\}$ and $G$ be a finite subgroup of $GL(V)$. The tensor algebra $T(V)$ over the complex is isomorphic to the polynomials in the non-commutative variables $x_1, x_2, \ldots, x_n$ with ...
Anouk Bergeron-Brlek, Christophe Hohlweg, Mike Zabrocki   +2 more
doaj   +1 more source

On Sparsity Conditions Guaranteeing a Fractional Coloring

Journal of Graph Theory, EarlyView.
ABSTRACT A graph has an ( a : b ) $(a:b)$ ‐coloring if there exists an assignment from the vertices to subsets of { 1 , … , a } $\{1,\ldots ,a\}$ with size b $b$ such that adjacent vertices are assigned disjoint subsets. Odd girth at least 2 k + 1 $2k+1$ is a necessary condition for a graph to have a ( 2 k + 1 : k ) $(2k+1:k)$‐coloring.
Ilkyoo Choi
wiley   +1 more source

A SURVEY INTUITIONISTIC FUZZY GRAPH [PDF]

Fiabilitate şi Durabilitate, 2018
I will begin with the presentation of the basic definitions required for the development of this survey- graph. Rosenfeld [5] first introduced the concept of fuzzy graphs. After that fuzzy graph theory becomes a vast research area. The first definition
Iuliana Carmen BĂRBĂCIORU, Viorica Mariela UNGUREANU   +1 more
doaj  

Quantum games and synchronicity [PDF]

Quantum
In the flavour of categorical quantum mechanics, we extend nonlocal games to allow quantum questions and answers, using quantum sets (special symmetric dagger Frobenius algebras) and the quantum functions of Musto, Reutter, and Verdon.
Adina Goldberg
doaj   +1 more source

Saturated Partial Embeddings of Planar Graphs

Journal of Graph Theory, EarlyView.
ABSTRACT In this work, we study how far one can deviate from optimal behavior when embedding a planar graph. For a planar graph G $G$, we say that a plane subgraph H ⊆ G $H\subseteq G$ is a plane‐saturated subgraph if adding any edge (possibly with new vertices) to H $H$ would either violate planarity or make the resulting graph no longer a subgraph of
Alexander Clifton, Nika Salia
wiley   +1 more source