منابع مشابه
Perfection thickness of graphs
We determine the order of growth of the worst-case number of perfect subgraphs needed to cover an n-vertex graph.
متن کاملPerfection for strong edge-coloring on graphs
A strong edge-coloring of a graph is a function that assigns to each edge a color such that every two distinct edges that are adjacent or adjacent to a same edge receive different colors. The strong chromatic index χs(G) of a graph G is the minimum number of colors used in a strong edge-coloring of G. From a primal-dual point of view, there are three natural lower bounds of χs(G), that is σ(G) ...
متن کاملt-Perfection in P5-Free Graphs
A graph is called t-perfect if its stable set polytope is fully described by non-negativity, edge and odd-cycle constraints. We characterise P5-free t-perfect graphs in terms of forbidden t-minors. Moreover, we show that P5-free t-perfect graphs can always be coloured with three colours, and that they can be recognised in polynomial time.
متن کاملThe Cost of Perfection for Matchings in Graphs
Perfect matchings and maximum weight matchings are two fundamental combinatorial structures. We consider the ratio between the maximum weight of a perfect matching and the maximum weight of a general matching. Motivated by the application in triangle meshes, where we seek to convert a triangulation into a quadrangulation by merging pairs of adjacent triangles, we focus on bridgeless cubic graph...
متن کاملThe perfection and recognition of bull-reducible Berge graphs
The recently announced Strong Perfect Graph Theorem states that the class of perfect graphs coincides with the class of graphs containing no induced odd cycle of length at least 5 or the complement of such a cycle. A graph in this second class is called Berge. A bull is a graph with five vertices x, a, b, c, d and five edges xa, xb, ab, ad, bc. A graph is bull-reducible if no vertex is in two b...
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ژورنال
عنوان ژورنال: Discrete Mathematics
سال: 2000
ISSN: 0012-365X
DOI: 10.1016/s0012-365x(99)00322-2