Two combinatorial statistics on Dyck paths
โ Scribed by Alain Denise; Rodica Simion
- Book ID
- 103059154
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 1003 KB
- Volume
- 137
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
โฆ Synopsis
Two combinatorial statistics, the pyramid weight and the number of exterior pairs, are investigated on the set of Dyck paths. Explicit formulae are given for the generating functions of Dyck paths of prescribed pyramid weight and prescribed number of exterior pairs. The proofs are combinatorial and rely on the method of q-grammars as well as on two new q-analogues of the Catalan numbers derived from statistics on non-crossing partitions. Connections with the combinatorics of Motzkin paths are pointed out.
๐ SIMILAR VOLUMES
A bijection is introduced in the set of all Dyck paths of semilength n from which it follows that (i) the parameters 'height of the first peak' and 'number of returns' have the same distribution and (ii) the parameter 'number of high peaks' has the Narayana distribution.