منابع مشابه
1-transitive Cyclic Orderings
We give a classification of all the countable 1-transitive cyclic orderings, being those on which the automorphism group acts singly transitively. We also classify all the countable 1-transitive coloured cyclic orderings, where these are countable cyclic orderings in which each point is assigned a member of a set C, thought of as its ‘colour’, and by ‘1transitivity’ we now mean that the automor...
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We derive a general result concerning cyclic orderings of the elements of a matroid. As corollaries we obtain two further results. The first corollary proves a conjecture of Gonçalves [7], stating that the circular arboricity of a matroid is equal to its fractional arboricity. This generalises a well-known result from Nash-Williams on covering graphs by spanning trees, and a result from Edmonds...
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A cyclic base ordering of a connected graph G is a cyclic ordering of E(G) such that every |V (G)−1| cyclically consecutive edges form a spanning tree ofG. LetG be a graph with E(G) ̸= ∅ and ω(G) denote the number of components in G. The invariants d(G) and γ(G) are respectively defined as d(G) = |E(G)| |V (G)|−ω(G) and γ(G) = max{d(H)}, where H runs over all subgraphs of G with E(H) ̸= ∅. A grap...
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ژورنال
عنوان ژورنال: Journal of Combinatorial Theory, Series A
سال: 2009
ISSN: 0097-3165
DOI: 10.1016/j.jcta.2008.08.006