418 research outputs found

    Perfect domination in regular grid graphs

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    We show there is an uncountable number of parallel total perfect codes in the integer lattice graph Ξ›{\Lambda} of R2\R^2. In contrast, there is just one 1-perfect code in Ξ›{\Lambda} and one total perfect code in Ξ›{\Lambda} restricting to total perfect codes of rectangular grid graphs (yielding an asymmetric, Penrose, tiling of the plane). We characterize all cycle products CmΓ—CnC_m\times C_n with parallel total perfect codes, and the dd-perfect and total perfect code partitions of Ξ›{\Lambda} and CmΓ—CnC_m\times C_n, the former having as quotient graph the undirected Cayley graphs of Z2d2+2d+1\Z_{2d^2+2d+1} with generator set {1,2d2}\{1,2d^2\}. For r>1r>1, generalization for 1-perfect codes is provided in the integer lattice of Rr\R^r and in the products of rr cycles, with partition quotient graph K2r+1K_{2r+1} taken as the undirected Cayley graph of Z2r+1\Z_{2r+1} with generator set {1,...,r}\{1,...,r\}.Comment: 16 pages; 11 figures; accepted for publication in Austral. J. Combi
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