Cyclic orderings and cyclic arboricity of matroids
نویسندگان
چکیده
منابع مشابه
Cyclic orderings and cyclic arboricity of matroids
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...
متن کامل1-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...
متن کاملCyclic Polytopes and Oriented Matroids
Consider the moment curve in the real Euclidean space R defined parametrically by the map γ : R → R, t → γ(t) = (t, t, . . . , t). The cyclic d-polytope Cd(t1, . . . , tn) is the convex hull of the n, n > d, different points on this curve. The matroidal analogues are the alternating oriented uniform matroids. A polytope [resp. matroid polytope] is called cyclic if its face lattice is isomorphic...
متن کاملEffect of Surgical Removal of Endometriomas on Cyclic and Non-cyclic Pelvic Pain
Background Endometriosis is a complex disease with a spectrum of pain symptoms from mild dysmenorrhea to debilitating pelvic pain. There is no concrete evidence in the literature whether endometriotic cyst per se, causes pain spectrum related to the disease. The aim of the present study was to evaluate the effect of surgical removal of endometriomas on pain symptoms. MaterialsAndMethods In this...
متن کاملCyclic base orderings in some classes of graphs
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...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Combinatorial Theory, Series B
سال: 2012
ISSN: 0095-8956
DOI: 10.1016/j.jctb.2011.08.004