|Monday 09/11/06||3:00 pm||A304 Wells Hall||Bruce Sagan||Counting permutations by congruence class of major index (1)|
|Monday 09/18/06||3:15 pm||A304 Wells Hall||Adam Goyt||Avoiding Partitions of a 3-element set (2)|
(1) Consider Sn, the symmetric group on n letters, and let majπ denote the major index of π∈ Sn. Given positive integers k,l and nonnegative integers i,j we define
(2) Patterns in permutations have been a topic of interest since the late 1970's. In the late 1990's Klazar introduced a notion of pattern avoidance in set partitions, and considered partitions of a 4-element set. We will discuss enumerative results of partitions avoiding partitions of a 3-element set. We will also consider enumerations of partitions avoiding generalized patterns.