Jake Levinson (Universit茅 de Montr茅al)
|
TITLE / TITRE A basic question about an algebraic variety X is how similar it is to projective space. One measure of similarity is the minimum degree of a rational map from X to projective space, called the degree of irrationality. This number, and the corresponding minimal-degree maps, are in general challenging to compute, but capture special features of the geometry of X. I will discuss some recent joint work with David Stapleton and Brooke Ullery on asymptotic bounds for degrees of irrationality of divisors X on projective varieties Y. Here, the minimal-degree rational maps $X \dashrightarrow \mathbb{P}^n$ turn out to "know" about Y and factor through rational maps $Y \dashrightarrow \mathbb{P}^n$ fibered in curves that are, in an appropriate sense, also听of minimal degree. Location: in person at UQAM PK-5675 or online at Zoom meeting 86352363947 听 |