Results 121 to 130 of about 728,495 (209)

Vertex-degree-based topological indices of uniform directed hypergraphs

Arab Journal of Basic and Applied Sciences
Modelling a chemical network is crucial for understanding the complex interactions and dynamics within a chemical system, allowing for precise predictions of reaction behaviour under various conditions.
Shashwath S. Shetty, K. Arathi Bhat
doaj   +1 more source

Linear trees in uniform hypergraphs

European Journal of Combinatorics, 2014
Given a tree T on v vertices and an integer k exceeding one. One can define the k-expansion T^k as a k-uniform linear hypergraph by enlarging each edge with a new, distinct set of (k-2) vertices. Then T^k has v+ (v-1)(k-2) vertices. The aim of this paper is to show that using the delta-system method one can easily determine asymptotically the size of ...
openaire   +3 more sources

Vertex-transitive self-complementary uniform hypergraphs

, 2008
In this paper we examine the orders of vertex-transitive self-complementary uniform hypergraphs. In particular, we prove that if there exists a vertex-transitive self-complementary k-uniform hypergraph of order n, where k=2ℓ or k=2ℓ+1 and n≡1(mod2ℓ+1 ...
Potočnik, Primož, Mateja Šajna, Šajna, Mateja, Primož Potočnik   +3 more
core   +1 more source

Wickets in 3-uniform hypergraphs

Discrete Mathematics
In these notes, we consider a Turán-type problem in hypergraphs. What is the maximum number of edges if we forbid a subgraph? Let $H_n^{(3)}$ be a 3-uniform linear hypergraph, i.e. any two edges have at most one vertex common. A special hypergraph, called {\em wicket}, is formed by three rows and two columns of a $3 \times 3$ point matrix.
openaire   +3 more sources

Constructing r-Uniform Hypergraphs with Restricted Clique Numbers [PDF]

, 2015
Ramsey theory has posed many interesting questions for graph theorists that have yet to be solved.  Many different methods have been used to find Ramsey numbers, though very few are actually known.
Budden, Mark, Rapp, Aaron
core  

On the number of $\mathcal {H}$ -free hypergraphs

Forum of Mathematics, Sigma
Two central problems in extremal combinatorics are concerned with estimating the number $\mathrm {ex}(n,\mathcal {H})$ , the size of the largest $\mathcal {H}$ -free hypergraph on n vertices, and the number $\mathrm {forb}(n,\mathcal {H})$
Tao Jiang, Sean Longbrake
doaj   +1 more source

Asymptotic Sharpness of Bounds on Hypertrees

Discussiones Mathematicae Graph Theory, 2017
The hypertree can be defined in many different ways. Katona and Szabó introduced a new, natural definition of hypertrees in uniform hypergraphs and investigated bounds on the number of edges of the hypertrees.
Lin Yi, Kang Liying, Shan Erfang
doaj   +1 more source

A note on self-complementary 4-uniform hypergraphs [PDF]

Opuscula Mathematica, 2005
We prove that a permutation \(\theta\) is complementing permutation for a \(4\)-uniform hypergraph if and only if one of the following cases is satisfied: (i) the length of every cycle of \(\theta\) is a multiple of \(8\), (ii) \(\theta\) has \(1\), \(2\)
Artur Szymański
doaj  

Correcting a Graph Into a Linegraph Minimizing Hamming Distance Edition Is NP-Complete and FPT by Treewidth

Journal of Graph Algorithms and Applications
Since Beineke's work in 1968 on linegraphs, attention has focused on the classification of graphs as linegraphs. It is known that every graph $G$ is the linegraph of an hypergraph, and the question is to characterize that root graph.
Dominique Barth, Dimitri Watel, Marc-Antoine Weisser   +2 more
doaj   +1 more source

3-Uniform hypergraphs of bounded degree have linear Ramsey numbers

, 2008
Chvátal, Rödl, Szemerédi and Trotter [V. Chvátal, V. Rödl, E. Szemerédi, W.T. Trotter Jr., The Ramsey number of a graph with a bounded maximum degree, J. Combin. Theory Ser. B 34 (1983) 239–243] proved that the Ramsey numbers of graphs of bounded maximum
Cooley, Oliver, Osthus, Deryk, Fountoulakis, Nikolaos; id_orcid, Kuhn, Daniela   +3 more
core   +1 more source