JCT
2010
13 years 6 months ago
2010
In the symmetric group on a set of size 2n, let P2n denote the conjugacy class of involutions with no fixed points (equivalently, we refer to these as “pairings”, since each ...
ENDM
2008
13 years 7 months ago
2008
The nth crossing number of a graph G, denoted crn(G), is the minimum number of crossings in a drawing of G on an orientable surface of genus n. We prove that for every a > b &g...
CCCG
2010
13 years 9 months ago
2010
Extending a bijection recently introduced by Poulalhon and Schaeffer [15] for triangulations of the sphere we design an efficient algorithm for encoding (topological) triangulatio...