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Post's closed systems and the weak chromatic number of hypergraphs

✍ Scribed by C. Benzaken

Publisher
Elsevier Science
Year
1978
Tongue
English
Weight
689 KB
Volume
23
Category
Article
ISSN
0012-365X

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✦ Synopsis

In the Post lattice of the families of closed systems (r.e. sets CT ooolean functions closed with respect to composition) the particular systems of mionotonic functions are closely related to the classitication of hypergraphs by their weak chromatic numbers. It is shown also that ffor k r 3, the k-chromatic hypergraphs can & built from the complete graph ,K Dans le treillis des sy&.mes clos de Post (i.e. des ensembles de fonctionu beolcermes clos par rapport B la composition des fonctions), les systbmes particuliers de fonctions croissantes sont itroitement rehes ii la classification des hypergraphes d'aprts leer nombre chromatique faible. On montrz aussi que pour k>3 les hypergraphts k-chromstiqties peuvent &tre construits 2 partir du :aaphe complet &.

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