Go Canada!

I’m honored to be visiting America’s virtuous neighbor to the north to speak in the PIMSUBC Math Distinguished Colloquium on Friday, September 14, 2018.

Title: Birational geometry and algebraic cycles

Abstract: A fundamental problem of algebraic geometry is to determine which algebraic varieties are rational, that is, isomorphic to projective space after removing lower-dimensional subvarieties from both sides. We discuss the history of the problem. Some dramatic progress in the past 5 years uses a new tool in this context: the Chow group of algebraic cycles.

On the day before, Thursday, September 13, I’ll speak in the UBC Algebraic Geometry seminar.

Title: Hodge theory of classifying stacks

Abstract: The goal of this talk is to create a correspondence between the representation theory of algebraic groups and the topology of Lie groups. The idea is to study the Hodge theory of the classifying stack of a reductive group over a field of characteristic p, the case of characteristic 0 having been studied by Behrend, Bott, Simpson and Teleman. The approach yields new calculations in representation theory, motivated by topology.


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SoCalAGS @ USC, 14 April 2018

The next Southern California Algebraic Geometry Seminar takes place at USC on Saturday, 14 April 2018. More information is available at the seminar webpage.

Our excellent slate of speakers is:
Ben Antieau (UIC)
Barbara Fantechi (Sissa)
Tommaso de Fernex (Utah)
Hiraku Nakajima (Kyoto)

Registration is free and very simple. Please register here.

Photo is by Julie Kitzenberger of a cat and pigeon who are friends. The 14th of April is pigeon day (25 Germinal) in the French Republican calendar.

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Update: I’ve realized posting this picture alone is possibly misleading. The picture, taken when Susie was about six months old, is a memorial. Susie died March 7, 2018, at the age of sixteen and a half years. She lived a pretty full life: after coming to us from London in a picnic basket (followed by several days being called Bill), Susie lived in Cambridge (UK and Massachusetts), Los Angeles, Seattle, and Princeton; had illustrious cat sitters; had a book dedicated to her; appeared in the Guardian; and most of all was very greatly loved.


March 8, 2018 · 12:45 am

WAGS @ San Francisco State, 17–18 March 2018

The Spring 2018 edition of the Western Algebraic Geometry Symposium (WAGS) is the weekend of 17–18 March 2018 at San Francisco State University. Details are now on the conference website.

Speakers are:
Linda Chen (Swarthmore)
José González (UC Riverside)
Antonella Grassi (Penn)
Alina Marian (Northeastern)
Jose Israel Rodriguez (Chicago)
Karen Smith (Michigan)
Richard Thomas (Imperial)

Photo: Tiger James looks to the new year.

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Past DLS Lecturers

Every year, the Distinguished Lecture Series (DLS) brings two to four eminent mathematicians to UCLA for a week or more to give a lecture series on their field, and to meet with faculty and graduate students.

Roman Bezrukavnikov
Igor Rodnianski
Claire Voisin
Geordie Williamson
Donald Goldfarb
Benedict Gross
Akshay Venkatesh
Manjul Bhargava
Andrei Okounkov
Robert Bryant
Peter Markowich
Yuval Peres
Michael Aizenman
Ursula Hamenstädt
László Lovász
Gilles Pisier
Richard Taylor
Jean-Pierre Wintenberger
Paul Seidel
Noga Alon
Michael Brenner
Pierre Colmez
Ehud Hrushovski
Michael Harris
Pierre-Louis Lions
Barry Mazur
Ken Ono
Leonid Polterovich
Horng-Tzer Yau
Gregory Margulis
Mario Bonk
John Coates
Elias Stein
Avi Wigderson
Charles Fefferman
C. David Levermore
Shing-Tung Yau
Shouwu Zhang
Peter Sarnak
Peter Schneider
Jean Bellissard
Etienne Ghys
Goro Shimura
Andrei Suslin
Zhengan Weng
Pierre Deligne
Michael Harris
Alexander Lubotzky
Hillel Furstenberg
Robert Langlands
Peter Lax
Nikolai Reshetikhin
Clifford Taubes
Shing-Tung Yau
Raoul Bott
L.H. Eliasson
Dennis Gaitsgory
Jesper Lutzen
Louis Nirenberg
Oded Schramm
I.M. Singer
Michael Atiyah
Jean-Michel Bismut
Alain Connes
Jöran Friberg
David Mumford
Gilles Pisier
Jean-Pierre Serre
Freydoon Shahidi
Gregg Zuckerman
Christophe Deninger
Nessim Sibony
Gang Tian

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Algebraic geometry session at AMS Fall Sectional Meeting @ UC Riverside, 4–5 November 2017

I’ll be speaking (on rationality) at the AMS Fall Sectional Meeting at Riverside. Other speakers in the algebraic geometry session are Aravind Asok, Emily Clader, Omprokash Das, Humberto Diaz, Matthias Flach, Martin Gallauer, James McKernan, Wenhao Ou, Dustin Ross, and Alexander Soibelman. The session is organized by Humberto Diaz, Jose Gonzalez, and Ziv Ran.

The invited addresses are by Paul Balmer, Pavel Etingof, and Monica Vazirani.


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New paper: The failure of Kodaira vanishing for Fano varieties, and terminal singularities that are not Cohen-Macaulay

I’ve posted a new paper on the arXiv. Most of the results premiered at Oberwolfach, but since then I’ve added an interesting new example inspired by related work of Takehiko Yasuda, whom I met there. (Oberwolfach at work!)

The paper shows that the Kodaira vanishing theorem can fail on smooth Fano varieties of any characteristic p > 0. Taking cones over some of these varieties, we give the first examples of terminal singularities which are not Cohen-Macaulay. By a different method, we construct a terminal singularity of dimension 3 (the lowest possible) in characteristic 2 which is not Cohen-Macaulay.

Image: Palmerston, Foreign Office cat, sneaks up on cheese; from his DiploMog twitter feed

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