The Algebraic Geometry Pre-Seminar takes place on Wednesdays 3:00–3:25PM in STON 215. Graduate students are particularly encouraged to attend. Note that when there is no external speaker, we may schedule pre-print seminar at 3:00–4:30PM in the same location.
September 9: Hyunsuk Kim (Imperial College London)
Location: Zoom
Title: Stanley's g-theorem
Abstract: For a simplicial polytope P, let f_i be the number of i-dimensional faces of P. What possible configuration of numbers can f_i be? For example, the famous Euler characteristic says that the alternating sum of these numbers should be 0 or 2. It turns out that there are many more relations of this sort. We will study Stanley's (and Billera–Lee's) g-theorem which completely characterizes the possible configurations of f_i's.