Skew Diagrams and Ordered Trees
β Scribed by Robert G. Rieper; Melkamu Zeleke
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 125 KB
- Volume
- 27
- Category
- Article
- ISSN
- 0196-8858
No coin nor oath required. For personal study only.
β¦ Synopsis
We use a known combinatorial argument to prove that among all ordered trees the ratio of the total number of vertices to leaves is two. We introduce a new combinatorial bijection on the set of these trees that shows why this must be so. Ordered trees are then enumerated by number of leaves, total path length, and number of vertices to obtain q-analogs of Catalan numbers. The results on ordered trees are then readily transferred by the skew diagrams to help enumerate parallelogram polyominoes by their area, perimeter, and other statistics.
π SIMILAR VOLUMES
of non-crossing partitions.
A bijection is introduced in the set of all ordered trees having n edges from which one derives that, for each positive integer q, the parameters "number of nodes of degree q" and "number of odd-level nodes of degree q-1" are equidistributed.