In some cases I've given more than one version of the talk, but I'm only including one version (usually the latest) here. These are all pdf files.
Rook Theory and Counting Permutations by Cycles , July 2000.
Rational Functions With Nonnegative Integer Coefficients , March 2003.
Symmetric Inclusion-Exclusion , April 2005.
Is Analysis Necessary?, October 2006.
Hankel determinants, continued fractions, orthgonal polynomials, and hypergeometric series , June 2007.
Counting Permutations by Putting Balls into Boxes, June 2007.
The Method of Coefficients , May 2008.Schröder Numbers, Large and Small, May 2009.
Chung-Feller Theorems, December 2009.
P-Partitions in Permutation Enumeration , December 2009.
Flag Descents and P-Partitions , January 2010.
Combinatorial Proofs of Congruences, January 2010.
The WZ method and zeta function identities , October 2010.
Descents, Peaks, and Shuffles of Permutations and Noncommutative Symmetric Functions , November 2010.
On the WZ Method, May 2011.
Integer quotients of factorials and algebraic multivariable hypergeometric series, September 2011.
The Carlitz-Scoville-Vaughan Theorem and its Generalizations, January 2013.
Rook Polynomials, January 2013.
Quotients of the Malvenuto-Reutenauer algebra and permutation enumeration, July 2013.
Rook Theory and Simplicial Complexes, January, 2015.
An Introduction to Symmetric Functions, June, 2016.
An Introduction to Combinatorial Species, June, 2016.
The Konvalinka-Amdeberhan conjecture and plethystic inverses, June, 2016.
Good Will Hunting’s Problem: Counting Homeomorphically Irreducible Trees, September, 2018.To Ira Gessel's home page