Displaying similar documents to “Multi-faithful spanning trees of infinite graphs”

Spanning caterpillars with bounded diameter

Ralph Faudree, Ronald Gould, Michael Jacobson, Linda Lesniak (1995)

Discussiones Mathematicae Graph Theory

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A caterpillar is a tree with the property that the vertices of degree at least 2 induce a path. We show that for every graph G of order n, either G or G̅ has a spanning caterpillar of diameter at most 2 log n. Furthermore, we show that if G is a graph of diameter 2 (diameter 3), then G contains a spanning caterpillar of diameter at most c n 3 / 4 (at most n).

End-faithful spanning trees of countable graphs with prescribed sets of rays

Norbert Polat (2001)

Czechoslovak Mathematical Journal

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We prove that a countable connected graph has an end-faithful spanning tree that contains a prescribed set of rays whenever this set is countable, and we show that this solution is, in a certain sense, the best possible. This improves a result of Hahn and Širáň Theorem 1.

Euler's idoneal numbers and an inequality concerning minimal graphs with a prescribed number of spanning trees

Jernej Azarija, Riste Škrekovski (2013)

Mathematica Bohemica

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Let α ( n ) be the least number k for which there exists a simple graph with k vertices having precisely n 3 spanning trees. Similarly, define β ( n ) as the least number k for which there exists a simple graph with k edges having precisely n 3 spanning trees. As an n -cycle has exactly n spanning trees, it follows that α ( n ) , β ( n ) n . In this paper, we show that α ( n ) 1 3 ( n + 4 ) and β ( n ) 1 3 ( n + 7 ) if and only if n { 3 , 4 , 5 , 6 , 7 , 9 , 10 , 13 , 18 , 22 } , which is a subset of Euler’s idoneal numbers. Moreover, if n ¬ 2 ( mod 3 ) and n 25 we show that α ( n ) 1 4 ( n + 9 ) and β ( n ) 1 4 ( n + 13 ) . This improves some previously estabilished...

Spanning tree congestion of rook's graphs

Kyohei Kozawa, Yota Otachi (2011)

Discussiones Mathematicae Graph Theory

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Let G be a connected graph and T be a spanning tree of G. For e ∈ E(T), the congestion of e is the number of edges in G joining the two components of T - e. The congestion of T is the maximum congestion over all edges in T. The spanning tree congestion of G is the minimum congestion over all its spanning trees. In this paper, we determine the spanning tree congestion of the rook's graph Kₘ ☐ Kₙ for any m and n.

Cyclic decompositions of complete graphs into spanning trees

Dalibor Froncek (2004)

Discussiones Mathematicae Graph Theory

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We examine decompositions of complete graphs with an even number of vertices, K 2 n , into n isomorphic spanning trees. While methods of such decompositions into symmetric trees have been known, we develop here a more general method based on a new type of vertex labelling, called flexible q-labelling. This labelling is a generalization of labellings introduced by Rosa and Eldergill.

On extremal sizes of locally k -tree graphs

Mieczysław Borowiecki, Piotr Borowiecki, Elżbieta Sidorowicz, Zdzisław Skupień (2010)

Czechoslovak Mathematical Journal

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A graph G is a if for any vertex v the subgraph induced by the neighbours of v is a k -tree, k 0 , where 0 -tree is an edgeless graph, 1 -tree is a tree. We characterize the minimum-size locally k -trees with n vertices. The minimum-size connected locally k -trees are simply ( k + 1 ) -trees. For k 1 , we construct locally k -trees which are maximal with respect to the spanning subgraph relation. Consequently, the number of edges in an n -vertex locally k -tree graph is between Ω ( n ) and O ( n 2 ) , where both bounds...