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Median graphs and Helly hypergraphs

✍ Scribed by H.M. Mulder; A. Schrijver


Publisher
Elsevier Science
Year
1979
Tongue
English
Weight
963 KB
Volume
25
Category
Article
ISSN
0012-365X

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πŸ“œ SIMILAR VOLUMES


On constructible graphs, locally Helly g
✍ Norbert Polat πŸ“‚ Article πŸ“… 2003 πŸ› John Wiley and Sons 🌐 English βš– 162 KB

## Abstract A (finite or infinite) graph __G__ is __constructible__ if there exists a well‐ordering ≀ of its vertices such that for every vertex __x__ which is not the smallest element, there is a vertex __y__ < __x__ which is adjacent to __x__ and to every neighbor __z__ of __x__ with __z__ < __x_

Cohomomorphisms of graphs and hypergraph
✍ Pavol Hell; Jaroslav NeΕ‘etΕ™il πŸ“‚ Article πŸ“… 1979 πŸ› John Wiley and Sons 🌐 English βš– 547 KB

In addition to a widely studied notion of homomorphisms of graphs and hypergraphs, [2, 5 , 6, 7, 9, 13, 141, we introduce the dual notion of cohomomorphisms. We shall concentrate on only a few aapects of these mappings, mostly with regard to intended applications, [lo, 111. Our basic motivation is t

Indecomposable regular graphs and hyperg
✍ ZoltΓ‘n FΓΌredi πŸ“‚ Article πŸ“… 1992 πŸ› Elsevier Science 🌐 English βš– 390 KB

Ftiredi, Z&an, Indecomposable regular graphs and hypergraphs, Discrete Mathematics 101 (1992) 59-64. Let G be a d-regular simple graph with n vertices. Here it is proved that for d > 6 -1, G contains a proper regular spanning subhypergraph. The same statement is proved for multigraphs with d > (n -1

Graph properties and hypergraph colourin
✍ Jason I. Brown; Derek G. Corneil πŸ“‚ Article πŸ“… 1991 πŸ› Elsevier Science 🌐 English βš– 855 KB

Given a graph property P, graph G and integer k 20, a P k-colouring of G is a function Jr:V(G)+ (1,. . ) k} such that the subgraph induced by each colour class has property P. When P is closed under induced subgraphs, we can construct a hypergraph HG such that G is P k-colourable iff Hg is k-colou

n-cubes and median graphs
✍ Martyn Mulder πŸ“‚ Article πŸ“… 1980 πŸ› John Wiley and Sons 🌐 English βš– 156 KB

## Abstract The n‐cube is characterized as a connected regular graph in which for any three vertices __u, v__, and __w__ there is a unique vertex that lies simultaneously on a shortest (__u, v__)‐path, a shortest (__v, w__)‐path, and a shortest (__w, u__)‐path.

Median graphs, parallelism and posets
✍ Jean-Pierre BarthΓ©lemy; Julien Constantin πŸ“‚ Article πŸ“… 1993 πŸ› Elsevier Science 🌐 English βš– 989 KB

A notion of parallelism is defined in finite median graphs and a number of properties about geodesics and the existence of cubes are obtained. Introducing sites as a double structure of partial order and graph on a set, it is shown that all median graphs can be constructed from sites and, in fact, t