35 research outputs found

    Path-factors involving paths of order seven and nine

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    In this paper, we show the following two theorems (here ci(Gβˆ’X)c_{i}(G-X) is the number of components CC of Gβˆ’XG-X with ∣V(C)∣=i|V(C)|=i): (i)~If a graph GG satisfies c1(Gβˆ’X)+13c3(Gβˆ’X)+13c5(Gβˆ’X)≀23∣X∣c_{1}(G-X)+\frac{1}{3}c_{3}(G-X)+\frac{1}{3}c_{5}(G-X)\leq \frac{2}{3}|X| for all XβŠ†V(G)X\subseteq V(G), then GG has a {P2,P7}\{P_{2},P_{7}\}-factor. (ii)~If a graph GG satisfies c1(Gβˆ’X)+c3(Gβˆ’X)+23c5(Gβˆ’X)+13c7(Gβˆ’X)≀23∣X∣c_{1}(G-X)+c_{3}(G-X)+\frac{2}{3}c_{5}(G-X)+\frac{1}{3}c_{7}(G-X)\leq \frac{2}{3}|X| for all XβŠ†V(G)X\subseteq V(G), then GG has a {P2,P9}\{P_{2},P_{9}\}-factor.Comment: 29 pages, 4 figure

    Forbidden subgraphs for constant domination number

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    In this paper, we characterize the sets H\mathcal{H} of connected graphs such that there exists a constant c=c(H)c=c(\mathcal{H}) satisfying Ξ³(G)≀c\gamma (G)\leq c for every connected H\mathcal{H}-free graph GG, where Ξ³(G)\gamma (G) is the domination number of GG.Comment: 6 pages, 1 figur
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