34 search results - page 3 / 7 » On the Number of Permutations Avoiding a Given Pattern |
COMBINATORICS
2000
13 years 7 months ago
2000
We find a generating function expressed as a continued fraction that enumerates ordered trees by the number of vertices at different levels. Several Catalan problems are mapped to...
DM
2007
13 years 7 months ago
2007
Several authors have examined connections between restricted permutations and Chebyshev polynomials of the second kind. In this paper we prove analogues of these results for color...
COMBINATORICS
2007
13 years 7 months ago
2007
For a permutation π = π1π2 · · · πn ∈ Sn and a positive integer i ≤ n, we can view π1π2 · · · πi as an element of Si by order-preserving relabeling. The j-set of ...
ENDM
2008
13 years 7 months ago
2008
We present a simple bijection between Baxter permutations of size n and plane bipolar orientations with n edges. This bijection translates several classical parameters of permutati...
ARSCOM
2005
13 years 7 months ago
2005
In [Kit1] Kitaev discussed simultaneous avoidance of two 3-patterns with no internal dashes, that is, where the patterns correspond to contiguous subwords in a permutation. In thre...