COMBINATORICS
1998
13 years 11 months ago
1998
Let F(n) be a family of partitions of n and let F(n d) denote the set of partitions in F(n) with Durfee square of size d. We de ne the Durfee polynomial of F(n) to be the polynomi...
COMBINATORICS
1998
13 years 11 months ago
1998
An n-Venn diagram is a collection of n finitely-intersecting simple closed curves in the plane, such that each of the 2n sets X1 ∩X2 ∩· · ·∩Xn, where each Xi is the open...
COMBINATORICS
1998
13 years 11 months ago
1998
The determinant that is present in traditional formulations of multivariate Lagrange inversion causes difficulties when one attempts to obtain asymptotic information. We obtain an...
COMBINATORICS
1998
13 years 11 months ago
1998
It is shown that there are 2n n − n−1 m=0 2n−m−1 2m m permutations which are the union of an increasing sequence and a decreasing sequence. 1991 Mathematics Subject Classi...
COMBINATORICS
1998
13 years 11 months ago
1998
The number of noncrossing partitions of {1, 2, . . . , n} with fixed block sizes has a simple closed form, given by Kreweras, and coincides with the corresponding number for nonne...
COMBINATORICS
1998
13 years 11 months ago
1998
Voltage graphs are a powerful tool for constructing large graphs (called lifts) with prescribed properties as covering spaces of small base graphs. This makes them suitable for ap...
COMBINATORICS
1998
13 years 11 months ago
1998
COMBINATORICS
1998
13 years 11 months ago
1998
Using Zeilberger’s factorization of two-stack-sortable permutations, we write a functional equation — of a strange sort — that defines their generating function according t...
COMBINATORICS
1998
13 years 11 months ago
1998
A multimatroid is a combinatorial structure that encompasses matroids, delta-matroids and isotropic systems. This structure has been introduced to unify a theorem of Edmonds on th...
COMBINATORICS
1998
13 years 11 months ago
1998
