The University of Michigan Combinatorics Seminar


Abstract 

Linear recurrences (and, with them, ordinary generating functions) are
ubiquitous in combinatorics, as part of a broad general framework that
is wellstudied and wellunderstood; in contrast, bilinear recurrences
such as
In this talk I will describe some types of combinatorial objects whose
properties make them wellsuited to a (nascent) general theory of bilinear
recurrence relations. In some interesting cases (e.g., the Somos4
recurrence given above), algebra is one step ahead of combinatorics, and
we are temporarily in the unusual position of being able to enumerate
combinatorial objects for which we lack a combinatorial description! 