Sciweavers

Share
COMBINATORICS
2006

Completion of the Wilf-Classification of 3-5 Pairs Using Generating Trees

8 years 11 months ago
Completion of the Wilf-Classification of 3-5 Pairs Using Generating Trees
A permutation is said to avoid the permutation if no subsequence in has the same order relations as . Two sets of permutations 1 and 2 are Wilfequivalent if, for all n, the number of permutations of length n avoiding all of the permutations in 1 equals the number of permutations of length n avoiding all of the permutations in 2. Using generating trees, we complete the problem of finding all Wilf-equivalences among pairs of permutations of which one has length 3 and the other has length 5 by proving that {123, 32541} is Wilf-equivalent to {123, 43251} and that {123, 42513} is Wilf-equivalent to {132, 34215}. In addition, we provide generating trees for fourteen other pairs, among which there are two examples of pairs that give rise to isomorphic generating trees.
Mark Lipson
Added 11 Dec 2010
Updated 11 Dec 2010
Type Journal
Year 2006
Where COMBINATORICS
Authors Mark Lipson
Comments (0)
books