Results 61 to 70 of about 698,372 (216)
Heliyon, 2022 Topological invariants are numerical parameters of graphs or hypergraphs that indicate its topology and are known as graph or hypergraph invariants. In this paper, topological indices of hypergraphs such as Wiener index, degree distance index and Gutman ...
Sakina Ashraf +3 more
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Bounded diameter monochromatic component covers
Mathematika, Volume 72, Issue 4, October 2026.Abstract Ryser conjectured that every r$r$‐edge‐coloured complete graph can be covered by r−1$r-1$ monochromatic trees. Motivated by a question of Austin in analysis, Milićević predicted something stronger — that every r$r$‐edge‐coloured complete graph can be covered by r−1$r-1$ monochromatic trees of bounded diameter.
Alexey Pokrovskiy
wiley +1 more source
Existential closure in uniform hypergraphs
Discrete MathematicsFor a positive integer $n$, a graph with at least $n$ vertices is $n$-existentially closed or simply $n$-e.c. if for any set of vertices $S$ of size $n$ and any set $T\subseteq S$, there is a vertex $x\not\in S$ adjacent to each vertex of $T$ and no vertex of $S\setminus T$.
Andrea C. Burgess +2 more
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Size of k-uniform hypergraph with diameter d [PDF]
, 2003 In this paper, we estimate the size of k-uniform hypergraph with diameter d, and give its minimum and ...
Ye, Miaolin
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Lower bounds for Ramsey numbers for complete bipartite and 3-uniform tripartite subgraphs
Journal of Graph Algorithms and Applications, 2013 Let R(Ka,b,Kc,d) be the minimum number n so that any n-vertex simple undirected graph G contains a Ka,b or its complement G′ contains a Kc,d. We demonstrate constructions showing that R(K2,b,K2,d) > b+d+1 for d ≥ b ≥ 2.
Tapas Kumar Mishra +1 more
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Recognizing the P_4-structure of claw-free graphs and a larger graph class [PDF]
Discrete Mathematics & Theoretical Computer Science, 2002 The P_4-structure of a graph G is a hypergraph \textbfH on the same vertex set such that four vertices form a hyperedge in \textbfH whenever they induce a P_4 in G.
Luitpold Babel +2 more
doaj +1 more source
The Evolution of Cooperation in Multigames with Uniform Random Hypergraphs
Mathematics, 2023 How to explain the emergence of cooperative behavior remains a significant problem. As players may hold diverse perceptions on a particular dilemma, the concept of multigames has been introduced.
Haozheng Xu +4 more
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On Tight Tree‐Complete Hypergraph Ramsey Numbers
Journal of Graph Theory, Volume 113, Issue 1, Page 88-96, September 2026.ABSTRACT Chvátal showed that for any tree T with k edges, the Ramsey number R ( T , n ) = k ( n − 1 ) + 1. For r = 3 or 4, we show that, if T is an r‐uniform nontrivial tight tree, then the hypergraph Ramsey number R ( T , n ) = Θ ( n r − 1 ). The 3‐uniform result comes from observing a construction of Cooper and Mubayi.
Jiaxi Nie
wiley +1 more source
Orientations of Graphs With at Most One Directed Path Between Every Pair of Vertices
Journal of Graph Theory, Volume 113, Issue 1, Page 143-164, September 2026.ABSTRACT Given a graph G, we say that an orientation D of G is a KT orientation if, for all u , v ∈ V ( D ), there is at most one directed path (in any direction) between u and v. Graphs that admit such orientations have been used to construct graphs with large chromatic number and small clique number that served as counterexamples to various ...
Barbora Dohnalová +3 more
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Colorful Subhypergraphs in Uniform Hypergraphs
The Electronic Journal of Combinatorics, 2017 There are several topological results ensuring in any properly colored graph the existence of a colorful complete bipartite subgraph, whose order is bounded from below by some topological invariants of some topological spaces associated to the graph. Meunier [Colorful subhypergraphs in Kneser hypergraphs, The Electronic Journal of Combinatorics, 2014 ...
openaire +4 more sources