منابع مشابه
Hamiltonian Colorings of Graphs with Long Cycles
By a hamiltonian coloring of a connected graph G of order n > 1 we mean a mapping c of V (G) into the set of all positive integers such that |c(x) − c(y)| > n − 1 − DG(x, y) (where DG(x, y) denotes the length of a longest x − y path in G) for all distinct x, y ∈ G. In this paper we study hamiltonian colorings of non-hamiltonian connected graphs with long cycles, mainly of connected graphs of or...
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by John Alan Engbers For graphs G and H, an H-coloring of G, or homomorphism from G to H, is an edge-preserving map from the vertices of G to the vertices of H. H-colorings generalize such graph theory notions as proper colorings and independent sets. In this dissertation, we consider four questions involving H-colorings of graphs. Recently, Galvin [27] showed that the maximum number of indepen...
متن کاملSome Results on List Total Colorings of Planar Graphs
Let G be a planar graph with maximum degree Δ. In this paper, it is proved that if Δ ≥ 9, then G is total-(Δ+2)-choosable. Some results on list total coloring of G without cycles of specific lengths are given.
متن کاملPerfect $2$-colorings of the Platonic graphs
In this paper, we enumerate the parameter matrices of all perfect $2$-colorings of the Platonic graphs consisting of the tetrahedral graph, the cubical graph, the octahedral graph, the dodecahedral graph, and the icosahedral graph.
متن کاملOn Irregular Colorings of Graphs
For a graph G and a proper coloring c : V (G) → {1, 2, . . . , k} of the vertices of G for some positive integer k , the color code of a vertex v of G (with respect to c ) is the ordered (k + 1) -tuple code(v) = (a0, a1, . . . , ak) where a0 is the color assigned to v and for 1 ≤ i ≤ k , ai is the number of vertices adjacent to v that are colored i . The coloring c is irregular if distinct vert...
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ژورنال
عنوان ژورنال: Discrete Applied Mathematics
سال: 2008
ISSN: 0166-218X
DOI: 10.1016/j.dam.2007.12.002