Print Friendly printer friendly
 Events
UBC
Mon 18 Nov 2019, 3:00pm
Algebraic Geometry Seminar
MATH 225
Biregular Cremona transformations of the plane
MATH 225
Mon 18 Nov 2019, 3:00pm-5:00pm

Abstract

We study the birational self-maps of the projective plane that induce bijections on the k-rational points for a given field k. These form a subgroup BCr_2(k) inside the Cremona group. The elements of BCr_2(k) are called Biregular Cremona transformations. We show that BCr_2(k) is not finitely-generated under a mild hypothesis on the field k. When k is a finite field, we study the possible permutations induced on the k-rational points of the plane. This is joint work with Kuan-Wen Lai, Masahiro Nakahara and Susanna Zimmermann.
hide
UBC
Mon 25 Nov 2019, 3:00pm
Algebraic Geometry Seminar
MATH 225
Projective bundle formula in derived cobordism theory
MATH 225
Mon 25 Nov 2019, 3:00pm-5:00pm

Abstract

I will introduce the universal precobordism theory, which generalizes algebraic cobordism of Levine-Morel to arbitrary quasi-projective schemes over a Noetherian base ring A. In the main part of the talk I will outline the proof of projective bundle formula for this new cohomology theory. The usual proof techniques based on resolution of singularities and weak factorization break down in this generality, so we have to use an alternative approach based on carefully studying the structure of precobordism rings of varieties with line bundles, which were inspired by a paper of Lee-Pandharipande. The talk is based on joint work with Shoji Yokura.
hide
Yu-Hsiang Liu
UBC
Mon 2 Dec 2019, 3:00pm
Algebraic Geometry Seminar
MATH 225
TBA
MATH 225
Mon 2 Dec 2019, 3:00pm-5:00pm

Abstract

 TBA
hide
 
Top