410 research outputs found

    Rainbow perfect matchings in r-partite graph structures

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    A matching M in an edge–colored (hyper)graph is rainbow if each pair of edges in M have distinct colors. We extend the result of Erdos and Spencer on the existence of rainbow perfect matchings in the complete bipartite graph Kn,n to complete bipartite multigraphs, dense regular bipartite graphs and complete r-partite r-uniform hypergraphs. The proof of the results use the Lopsided version of the Local Lovász Lemma.Peer ReviewedPostprint (author's final draft

    Large rainbow matchings in large graphs

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    A \textit{rainbow subgraph} of an edge-colored graph is a subgraph whose edges have distinct colors. The \textit{color degree} of a vertex vv is the number of different colors on edges incident to vv. We show that if nn is large enough (namely, n≥4.25k2n\geq 4.25k^2), then each nn-vertex graph GG with minimum color degree at least kk contains a rainbow matching of size at least kk

    Existences of rainbow matchings and rainbow matching covers

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    Let GG be an edge-coloured graph. A rainbow subgraph in GG is a subgraph such that its edges have distinct colours. The minimum colour degree δc(G)\delta^c(G) of GG is the smallest number of distinct colours on the edges incident with a vertex of GG. We show that every edge-coloured graph GG on n≥7k/2+2n\geq 7k/2+2 vertices with δc(G)≥k\delta^c(G) \geq k contains a rainbow matching of size at least kk, which improves the previous result for k≥10k \ge 10. Let Δmon(G)\Delta_{\text{mon}}(G) be the maximum number of edges of the same colour incident with a vertex of GG. We also prove that if t≥11t \ge 11 and Δmon(G)≤t\Delta_{\text{mon}}(G) \le t, then GG can be edge-decomposed into at most ⌊tn/2⌋\lfloor tn/2 \rfloor rainbow matchings. This result is sharp and improves a result of LeSaulnier and West
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