Permutations avoiding connected graphs
There is a permutation of the vertices of a tree for which no proper subtree on at least two vertices is mapped to a subtree, if and only if twice the number of its endpoints is less than or equal to the number of points of the tree; Theorem 4.1. The following more general result follows: Let G = (V...
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Published in | Contributions to discrete mathematics Vol. 12; no. 2 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
27.11.2017
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Online Access | Get full text |
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Summary: | There is a permutation of the vertices of a tree for which no proper subtree on at least two vertices is mapped to a subtree, if and only if twice the number of its endpoints is less than or equal to the number of points of the tree; Theorem 4.1. The following more general result follows: Let G = (V (G), E(G)) be a simple graph and let C(G) be the set of subsets A V (G) which induce a connected subgraph of G containing at least two vertices and let Π(G) be the set of permutations of V (G) which do not map an element of C(G) to an element of C(G). In the case where G has n vertices and at most n − 1 edges we give a necessary and sufficient condition on G so that Π(G) [SPECIAL CHARACTER]= ∅. AMS subject classification (2000): 05C70 |
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ISSN: | 1715-0868 1715-0868 |
DOI: | 10.55016/ojs/cdm.v12i2.62745 |