JCT
2010
13 years 10 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 11 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
14 years 27 days 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...