1215 search results - page 105 / 243 » Combinatorics |
97
Voted
COMBINATORICS
2006
15 years 3 months ago
2006
We show that matchings avoiding certain partial patterns are counted by the 3-Catalan numbers. We give a characterization of 12312-avoiding matchings in terms of restrictions on t...
110
click to vote
COMBINATORICS
2006
15 years 3 months ago
2006
Previous work has shown the perhaps surprising result that, for any binary phylogenetic tree T , there is a set of four characters that define T . Here we deal with the general ca...
125
Voted
COMBINATORICS
2006
15 years 3 months ago
2006
Sommerville [10] and Davies [2] classified the spherical triangles that can tile the sphere in an edge-to-edge fashion. Relaxing this condition yields other triangles, which tile ...
COMBINATORICS
2006
15 years 3 months ago
2006
One way to choose a basis of a matroid at random is to choose an ordering of the ground set uniformly at random and then use the greedy algorithm to find a basis. We investigate t...
125
click to vote
COMBINATORICS
2006
15 years 3 months ago
2006
A spanning tree T in a finite planar connected graph G determines a dual spanning tree T in the dual graph G such that T and T do not intersect. We show that it is not always poss...