Graphs with the Erdos-Ko-Rado property

dc.creatorHolroyd, Fred
dc.creatorTalbot, John
dc.date2003-07-04
dc.date.accessioned2026-07-07T04:59:26Z
dc.date.available2026-07-07T04:59:26Z
dc.descriptionFor a graph G and integer r \geq 1 we denote the family of independent r-sets of V(G) by I^{(r)}(G). A graph G is said to be r-EKR if no intersecting subfamily of I^{(r)}(G) is larger than the largest such family all of whose members contain some fixed v \in V(G). If this inequality is always strict, then G is said to be strictly r-EKR. We show that if a graph G is r-EKR then its lexicographic product with any complete graph is r-EKR. For any graph G, we define μ(G) to be the minimum size of a maximal independent vertex set. We conjecture that, if 1 \leq r \leq 1/2μ(G), then G is r-EKR, and if r<1/2μ(G), then G is strictly r-EKR. This is known to be true when G is an empty graph, a cycle, a path or the disjoint union of complete graphs. We show that it is also true when G is the disjoint union of a pair of complete multipartite graphs.
dc.description15 pages, 2 figures, submitted to Discrete Mathematics (BCC19 issue)
dc.identifierhttps://arxiv.org/abs/math/0307073
dc.identifierhttp://arxiv.org/abs/math/0307073
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/67986
dc.subjectCombinatorics
dc.subject05D05; 05C35
dc.titleGraphs with the Erdos-Ko-Rado property
dc.typetext

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