Combinatorics Seminar- Involutions and pseudo-involutions in the Riordan group

Speaker: Alex Burstein, Howard University
Date and time: Thursday, October 25, 4-5pm
Place:  Phillips 110
Title: Involutions and pseudo-involutions in the Riordan group

Abstract:  We define the Riordan group and consider its involutions and pseudo-involutions, as well as A- and B-sequences of Riordan matrices. We then look at one elementary method, via palindromes, for producing pseudo-involutions associated with many well-known combinatorial sequences.  This unified approach yields both classical cases and new(er) examples, some with interesting combinatorial interpretations.  Finally, we give a combinatorial interpretation of some pseudo-involutions via Parker's generalization of the Carlitz-Scoville-Vaughn theorem.  This is joint work with Lou Shapiro.