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COMBINATORICA
2006
14 years 9 months ago
2006
Let T be a fixed tournament on k vertices. Let D(n, T) denote the maximum number of orientations of an n-vertex graph that have no copy of T. We prove that D(n, T) = 2tk-1(n) for ...
COMBINATORICA
1998
14 years 9 months ago
1998
We prove that the total chromatic number of any graph with maximum degree is at most plus an absolute constant. In particular, we show that for su ciently large, the total chromat...
COMBINATORICA
2008
14 years 9 months ago
2008
We give a simple proof for a theorem of Katchalski, Last, and Valtr, asserting that the maximum number of edges in a geometric graph G on n vertices with no pair of parallel edges...
COMBINATORICA
2008
14 years 9 months ago
2008
We show that if a graph G has the property that all subsets of vertices of size n/4 contain the "correct" number of triangles one would expect to find in a random graph ...
COMBINATORICA
2008
14 years 9 months ago
2008
Describing minimal generating sets of toric ideals is a well-studied and difficult problem. Neil White conjectured in 1980 that the toric ideal associated to a matroid is generated...