2025 Sue Geller Undergraduate Lecture 

 Abstract:  Part of combinatorics looks for nice formulas to count various objects.  Sometimes these formulas hide an added surprise:   when we introduce a variable to turn them into a polynomial, they count the objects with cyclic symmetry, after plugging in a complex root-of-unity for the variable!   We will illustrate this with some of our favorite examples, including some that we still find mysterious.

 Bio of Victor Reiner:    Victor Reiner is a Distinguished McKnight Professor in Mathematics at the University of Minnesota.  He received his AB in 1986 from Princeton, and his PhD in 1990 from MIT, advised by Richard Stanley.  He has received an NSF Postdoc Fellowship, and a Sloan Fellowship, is a Fellow of the AMS, and served as a member-at-large  on the AMS Council.

His research interests are in combinatorics.  He has advised 20 PhD students, many summer REU students, and has served on the editorial boards of Journal of the AMS, Algebra and Number Theory, Journal of Algebraic Combinatorics, Journal of Combinatorial Theory Series A, ORDER, Algebraic Combinatorics, and Combinatorial Theory.  

He is keenly interested in promoting diamond open access publishing in math.