Search results for "Dyck path"
showing 2 items of 2 documents
The pure descent statistic on permutations
2017
International audience; We introduce a new statistic based on permutation descents which has a distribution given by the Stirling numbers of the first kind, i.e., with the same distribution as for the number of cycles in permutations. We study this statistic on the sets of permutations avoiding one pattern of length three by giving bivariate generating functions. As a consequence, new classes of permutations enumerated by the Motzkin numbers are obtained. Finally, we deduce results about the popularity of the pure descents in all these restricted sets. (C) 2017 Elsevier B.V. All rights reserved.
Counting Prefixes of Skew Dyck Paths
2021
We present enumerative results on prefixes of skew Dyck paths by giving recursive relations, Riordan arrays, and generating functions, as well as closed formulas to count the total number of these paths with respect to the length, the height of its endpoint and the number of left steps.