Bricks and conjectures of Berge, Fulkerson and Seymour
نویسندگان
چکیده
An r-graph is an r-regular graph where every odd set of vertices is connected by at least r edges to the rest of the graph. Seymour conjectured that any r-graph is r + 1edge-colorable, and also that any r-graph contains 2r perfect matchings such that each edge belongs to two of them. We show that the minimum counter-example to either of these conjectures is a brick. Furthermore we disprove a variant of a conjecture of Fan, Raspaud.
منابع مشابه
Perfect matching covering, the Berge-Fulkerson conjecture, and the Fan-Raspaud conjecture
Let m∗t be the largest rational number such that every bridgeless cubic graph G associated with a positiveweightω has t perfectmatchings {M1, . . . ,Mt}withω(∪i=1 Mi) ≥ m ∗ t ω(G). It is conjectured in this paper that m∗3 = 4 5 , m ∗ 4 = 14 15 , and m ∗ 5 = 1, which are called the weighted PM-covering conjectures. The counterparts of this new invariant m∗t and conjectures for unweighted cubic g...
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ورودعنوان ژورنال:
- CoRR
دوره abs/1003.5782 شماره
صفحات -
تاریخ انتشار 2010