## Math Calendar

Monday, January 22, 2018
08:59-10:40
BBG023
Orientation on Mathematical Research Student Presentations (a-c)
09:00-09:30
(a) An alternative probability theory based on belief functions
09:35-10:05
(b) The homotopy transfer theorem
10:10-10:40
(c) Supersingular Isogeny Diffie–Hellman
Tuesday, January 23, 2018
12:00-13:00
HFG Library

Introduction of new colleagues
presentation: U Talent - math activities for pupils and teachers (Ragna Senf & Anita Kokelaar)
presentation: Social and scientific confusion from mathematics (Ferdinand Verhulst)
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
Julie Desjardins (MPIM Bonn) - Square-free values of a polynomial (and elliptic curves)
Abstract: Let f be a primitive separable polynomial of positive degree in Z[T]. A number theory question : is there infinitely many values f(t) with no square factors ? It is conjectured that the answer is yes, and even more precisely, that a positive proportion of the values are square-free. This is known as the square-free conjecture. In 1953, Erdös showed that for cubics there are infinitely many square-free values, and in 1967, Hooley showed positive proportion when deg=3. The conjecture is still not known for irreducible polynomials of degree greater than 3.
In this talk, we relate this problem to its main motivation: the study of the variation of the analytic rank in a family
of elliptic curves.
Thursday, January 25, 2018
16:00-17:00
HFG 611
Complex Systems Seminar
Isabelle Schneider (Berlin) - TBA
Title:
Abstract:
Monday, January 29, 2018
11:00-12:00
HFG 610
Extra Talk
Adrien Sauvaget (Jussieu) - Volumes and Siegel-Veech constants of $\mathcal{H}(2g-2)$ and Hodge integrals

Abstract:
The Hodge bundle is stratified according to the set of zeros of the differential. In the 80's H. Masur and W. Veech defined two numerical invariants of these strata: the volume and the Siegel-Veech constants.
<br />Based on numerical experiments, A. Eskin and A. Zorich proposed a series of conjectures for the large genus asymptotic of these invariants. By a careful analysis of the asymptotic behavior of quasi-modular forms, D. Chen, M. Moeller, and D. Zagier proved this conjecture for strata of differentials with simple zeros. We will explain how to prove that the conjecture holds in the other extreme case,  i.e. for strata of differentials with a unique zero. The main ingredient is the expression of the volumes of these strata in terms of Hodge integrals on moduli spaces of curves.
<br />
16:00-18:00
KBG Atlas
Movie preview
Galois - Story of a revolutionary mathematician
Tuesday, January 30, 2018
11:00-12:00
HFG 610
Utrecht Geometry Center Seminar
Cecília Salgado (MPIM Bonn/Instituto de Matemática - UFRJ) - Elliptic fibrations on K3 surfaces and linear systems of curves on rational surfaces
Abstract: We consider K3 surfaces which are double covers of rational elliptic surfaces. The former is endowed with a natural elliptic fibration, which is induced by the latter. These K3 surfaces admit other elliptic fibrations, which are necessarily induced by special linear systems on the rational elliptic surfaces. We describe these linear systems in terms of the non-symplectic (deck) involution. In particular, every conic bundle on the rational surface induces a genus 1 fibration on the K3. We classify the singular fibers of the genus 1 fibration on the K3 surface it terms of singular fibers and special curves on the conic bundle on the rational surface. This is joint work with A. Garbagnati - U. Millano.
15:30-16:00
HFG Library
Institute Tea
Tuesday, February 6, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
Leila Schneps (Parijs) - t.b.a.
Thursday, February 8, 2018
16:00-17:00
HFG 611
Complex Systems Seminar
Michiel Hochstenbach (TU/e) - TBA
Title:
Abstract:
Tuesday, February 13, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
Lennart Meier (UU) - t.b.a.
Thursday, February 15, 2018
16:00-17:00
HFG 611
Complex Systems Seminar
Hans Oude Groeniger (UU) - TBA
Title:
Abstract:
Tuesday, February 20, 2018
12:00-13:00
HFG Library
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
Dustin Clausen (Copenhagen) - t.b.a.
Tuesday, February 27, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
Arne Smeets (Radboud Universiteit Nijmegen) - On the diophantine complexity of p-adic fields
Abstract

There are various notions of the diophantine 'complexity' or 'dimension' of a given field. Given any such notion, algebraically closed fields are the simplest ones. At the next level, one usually finds the finite fields and their 'neighbours'. Yet another step up in complexity, the so-called p-adic fields come into the picture.

I will discuss the properties of p-adic fields from the point of view of one particular notion of diophantine complexity, introduced by Serge Lang in the sixties. This will lead us to the theory of polynomial equations in 'many' variables, the celebrated Ax-Kochen theorem and some model theory.

Next, I will discuss a recent improvement to the Ax-Kochen theorem obtained in joint work by Dan Loughran, Alexei Skorobogatov and the speaker. Our approach to the problem makes heavy use of birational and toroidal geometry, and builds on work of Colliot-Thélène and Denef.
Tuesday, March 6, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
Jenya Sapir (MPIM Bonn/UIUC) - t.b.a.
Tuesday, March 13, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
Pieter Belmans (MPI Bonn) - t.b.a.
Tuesday, March 20, 2018
12:00-13:00
HFG Library
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
Renee Hoekzema (Oxford) - t.b.a.
Thursday, March 22, 2018
15:30-16:30
KBG Atlas
The Utrecht Mathematical Colloquium
Georg Dolzmann (Universität Regensburg) - TBA
Tuesday, March 27, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
Jakub Byszewski (Jagiellonian University) - t.b.a.
Tuesday, April 3, 2018
15:30-16:00
HFG Library
Institute Tea
Tuesday, April 10, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
Anna Haensch (Duquesne University/MPIM Bonn) - t.b.a.
Tuesday, April 17, 2018
12:00-13:00
HFG Library
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
Robert van der Vorst (VU Amsterdam) - t.b.a.
Tuesday, April 24, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
Jaclyn Lang (MPIM Bonn) - t.b.a.
Tuesday, May 1, 2018
15:30-16:00
HFG Library
Institute Tea
Tuesday, May 8, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
t.b.a. () - t.b.a.
Tuesday, May 15, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
t.b.a. () - t.b.a.
Thursday, May 17, 2018
16:00-17:00
HFG 611
Complex Systems Seminar
Bezoeker Kreisbeck (UU) - TBA
Title:
Abstract:
Tuesday, May 22, 2018
12:00-13:00
HFG Library
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
t.b.a. () - t.b.a.
Tuesday, May 29, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
t.b.a. () - t.b.a.
Tuesday, June 5, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
Clément Dupont (Université de Montpellier) - t.b.a.
Tuesday, June 12, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
t.b.a. () - t.b.a.
Tuesday, June 19, 2018
12:00-13:00
HFG Library
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
t.b.a. () - t.b.a.
Tuesday, June 26, 2018
15:30-16:00
HFG Library
Institute Tea
16:00-17:00
HFG 611
Utrecht Geometry Center Seminar
t.b.a. () - t.b.a.
Tuesday, July 3, 2018
15:30-16:00
HFG Library
Institute Tea
Tuesday, July 10, 2018
15:30-16:00
HFG Library
Institute Tea
Tuesday, July 17, 2018
15:30-16:00
HFG Library
Institute Tea