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出典:『Wikipedia』 (2010/10/07 13:06 UTC 版)

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In combinatorial mathematics, LCF notation or LCF code is a notation devised by Joshua Lederberg, and extended by Coxeter and Frucht, for the representation of cubic graphs that are Hamiltonian. Since the graphs are Hamiltonian, the vertices can be arranged in a cycle, which accounts for two edges per vertex. The third edge from each vertex can then be described by how many positions clockwise (positive) or counter-clockwise (negative) it leads. Often the pattern repeats, which is indicated by a superscript in the notation. For example, the Nauru graph, shown on the right, has LCF notation [5, −9, 7, −7, 9, −5]⁴. Graphs may have different LCF notations, depending on precisely how the vertices are arranged.