Title: Enumerating permutations with exactly r copies of a pattern
Speaker: Brian Nakamura, CCICADA/DIMACS, Rutgers University
Date: Tuesday, September 10, 2013 11:00am - 12:00pm
Location: DIMACS Center, CoRE Bldg, Room 431, Rutgers University, Busch Campus, Piscataway, NJ
Abstract:
The study of patterns in permutations gained interest after some early results on permutation sorting. This naturally led to enumerative questions such as "How many length n permutations avoid a given pattern?" I will begin by providing some background and then discuss a generalization to the avoidance problem, where one is now interested in permutations with exactly r copies of a pattern. I will present a functional equations approach to derive a new enumeration algorithm. I will discuss what types of patterns this approach works for (so far) and also how this approach can be extended to multiple patterns.