In lieu of an abstract I offer a problem. Consider three billiard balls of the same radius and mass, undergoing totally elastic reflections on a billiard table with no walls (the whole plane). All three balls can be given non-zero initial velocities. What is the maximum (supremum) possible number of collisions among the three balls? The supremum is taken over all initial positions and initial velocities. I will discuss this problem and its generalization to any finite family of balls in one, two and higher dimensions. Joint work with Jayadev Athreya and Mauricio Duarte.
On the number of collisions of billiard balls
Nov. 12, 2019 1pm (MATH 220)
Grad Algebra/Logic
Peter Mayr (CU) Finiteness conditions for subdirect products 2
Nov. 12, 2019 4pm (MATH 350)
Topology
Robin Deeley (CU Boulder) The Stratification of the Moduli Stack of Formal Groups
On the number of collisions of billiard balls