| Tuesday, March 12 Colloquium Time: 15:30 Room: MC 108 Speaker: Frank Sottile (Texas A&M University) Title: Webs and Welschinger signs |
Colloquium Time: 15:30 Room: MC 107 Speaker: Frank Sottile (Texas A&M University) Title: Webs and Welschinger signs A 3-dimensional subspace f of real polynomials defines a map f : P^1 -> P^2 whose image is a rational plane curve. It is maximally inflected when all of its flexes are real, equivalently, when its Wronski determinant has only real roots. We associate two a priori distinct signs (\pm 1) to f: the Welschinger invariant of the rational curve and the degree of the Wronski map at f. Extensive computation suggests that these signs coincide. While studying this conjecture we were led to a deeper conjecture: From f, we define a a function W : CP^1 -> CP^1 which encodes some real geometry of f and conjecturally gives an object called a web. We conjecture that known bijections between webs and standard Young tableaux and between tableaux and maximally inflected curves recovers the curve.This talk will explain this picture with compelling evidence and beautiful pictures. It is joint work with Brazelton, Karp, Le, Levinson, McKean, Peltola, and Speyer. |
| Wednesday, March 13 Algebra Seminar Time: 14:30 Room: MC 108 Speaker: Stefan Gille (University of Alberta) Title: Stronger versions of Rost nilpotence Given two Chow motives M and N satisfying Rost nilpotence, a natural question is whether their direct sum has the same property. Rather obviously this question is closely related to the famous and old Köthe conjecture. If this conjecture is true the answer to above question is yes. However it seems that most ring theorists believe Köthe's conjecture does not hold. This leads to studying stronger versions of Rost nilpotence, which (surprisingly?) hold in (almost?) all cases where usual Rost nilpotence is known, as I will explain in my talk. |
Algebra Seminar Time: 14:30 Room: MC 108 Speaker: Stefan Gille (University of Alberta) Title: Stronger versions of Rost nilpotence Given two Chow motives M and N satisfying Rost nilpotence, a natural question is whether their direct sum has the same property. Rather obviously this question is closely related to the famous and old Kothe conjecture. If this conjecture is true the answer to above question is yes. However it seems that most ring theorists believe Kothe's conjecture does not hold. This leads to studying stronger versions of Rost nilpotence, which (surprisingly?) hold in (almost?) all cases where usual Rost nilpotence is known, as I will explain in my talk. |