COMBINATORICS
1999
13 years 11 months ago
1999
Let k denote the maximum degree of the kth iterated line graph Lk(G). For any connected graph G that is not a path, the inequality k+1 2k - 2 holds. Niepel, Knor, and Solt
COMBINATORICS
1999
13 years 11 months ago
1999
This is a continuation of our paper "A Theory of Pfaffian Orientations I: Perfect Matchings and Permanents". We present a new combinatorial way to compute the generating...
COMBINATORICS
1999
13 years 11 months ago
1999
Kasteleyn stated that the generating function of the perfect matchings of a graph of genus g may be written as a linear combination of 4g Pfaffians. Here we prove this statement. ...
COMBINATORICS
1999
13 years 11 months ago
1999
It is proven that for every fixed h, a and b, a graph with n vertices and minimum degree at least h-1 h n, which contains no copy of Kb (the complete graph with b vertices), conta...
COMBINATORICS
1999
13 years 11 months ago
1999
We define and study m-closed cellular algebras (coherent configurations) and m-isomorphisms of cellular algebras which can be regarded as mth approximations of Schurian algebras (...
COMBINATORICS
1999
13 years 11 months ago
1999
We compute the number of rhombus tilings of a hexagon with sides n, n, N, n, n, N, where two triangles on the symmetry axis touching in one vertex are removed. The case of the comm...
COMBINATORICS
1999
13 years 11 months ago
1999
A Steiner triple system has a bicoloring with m color classes if the points are partitioned into m subsets and the three points in every block are contained in exactly two of the ...
COMBINATORICS
1999
13 years 11 months ago
1999
We study the 2-adic behavior of the number of domino tilings of a 2n
COMBINATORICS
1999
13 years 11 months ago
1999
Let G = (V, E) be an undirected graph. Let C be a subset of vertices that we shall call a code. For any vertex v V , the neighbouring set N(v, C) is the set of vertices of C at d...
COMBINATORICS
1999
13 years 11 months ago
1999
