7 search results - page 2 / 2 » Enumeration of permutations by number of alternating descent... |
COMBINATORICS
2002
14 years 9 months ago
2002
: We generalize the notion of pattern avoidance to arbitrary functions on ordered sets, and consider specifically three scenarios for permutations: linear, cyclic and hybrid, the f...
EJC
2006
14 years 9 months ago
2006
Abstract. A leaf of a plane tree is called an old leaf if it is the leftmost child of its parent, and it is called a young leaf otherwise. In this paper we enumerate plane trees wi...