# Events

# Events 2008

**DIAMANT meets GQT
**

*October 27th, 2008*

From 27-31 October the workshop “DIAMANT meets GQT” takes place at the Lorentz Center, Leiden. The first three days are reserved for the “Studygroup DIAMANT with GQT”, and focus on attacking selected open mathematical problems. In the last two days the “DIAMANT/GQT-symposium” takes place, where also results on the problems are presented.

The format of the first three days is inspired by that of the yearly “Studygroup Mathematics with Industry”. Monday morning a small number of problems are presented. Then the participants are partitioned into groups and work on the the problems until Wednesday afternoon.

**GQT colloquium Utrecht
**

*September 26th, 2008*

On September 26 (2008), from 11.00-17.00 there will be the first GQT-colloquium of the academic year 2008/2009. It will be held in Utrecht, room 503 of the Buys Ballot Laboratorium, Princetonplein 5 (directions, see http://www.cs.uu.nl/docs/reach/bbl.php ). Speakers are Bernardo Uribe (Universidad de Los Andes, Colombia, temporarily MPI, Bonn), Michael Polyak (Technion, Israel, temporarily MPI, Bonn) and Gil Cavalcanti (Mathematisch Instituut, Utrecht).

**Utrecht General Colloquium Talk by Sergey Shadrin (UvA)
**

*September 18th, 2008*

Title: Cohomological Field Theory.

Location and time: Utrecht University, Mathematics Building, room 611; 15:30 – 16:30.

**Afscheidsvoordracht Dirk Siersma
**

*September 10th, 2008*

Op 10 september a.s. houdt Dirk Siersma zijn afscheidsrede “Leven met Wiskunde” in de Aula van het Academiegebouw van de Universiteit Utrecht. Aanvang 16.15 uur.

Na afloop receptie in de Senaatszaal.

Voorafgaand aan het afscheidscollege vindt vanaf 10.30 uur een wetenschappelijk meetkundesymposium plaats in de aangrenzende Faculty Club Helios, Achter de Dom 7A Utrecht.

**Symposium Meetkunde
**

*September 10th, 2008*

Ter gelegenheid van het emeritaat van Prof.dr. Dirk Siersma.

Lokatie: Faculty Club Helios, Achter de Dom 7A Utrecht (achter het academiegebouw).

Programma:

10.30-11.30 Ontvangst met koffie en thee.

11.00-12.00 Mihai Tibar (Lille): Walk in the forest of Milnor fibrations

Lunch

13.14-14.15 Aad Goddijn (Utrecht): “de hooge gekromde blauwe RUIMTE BEN IK” over de vierde dimensie bij Theo van Doesburg.

14.30-15.30 Duco van Straten (Mainz): The algebra and topology of line singularities.

Na afloop begint om 16.15 uur het afscheidscollege in de Aula van de Universiteit Utrecht, gevolgd door een receptie.

**Workshop Sheaves in Geometry and Quantum Theory
**

*September 3rd, 2008*

This is to announce a three-day workshop on the interplay between logic, topology/geometry and quantum theory Sheaves in Geometry and Quantum theory ; September 3-5, 2008 Radboud University Nijmegen, the Netherlands ; funded by the Fellowship of Geometry and Quantum Theory (GQT-cluster) and Stichting Compositio Mathematica. For more information click on the header above.

Invited (confirmed) speakers are: Andreas Doering (Imperial College London), Anders Kock (Aarhus), Jaap van Oosten (Utrecht), Erik Palmgren (Uppsala), Pedro Resende (Lisbon), Isar Stubbe (Antwerp), and Steve Vickers (Birmingham)

Registration is free, but for logistic reasons, please inform Chris Heunen (heunen@math.ru.nl) if you plan to attend.

**Minisymposium on “Applications of Noncommutative Geometry” at 5ecm
**

*July 14th, 2008*

Amsterdam, July 14th – 18th, 2008

List of speakers:

**Caterina Consani** (Johns Hopkins)

**Yuri Manin** (MPIM/Northwestern)

**Pedro Resende** (Lisboa)

**Walter van Suijlekom** (Radboud Universiteit)

see also the plenary talk of **Matilde Marcolli** (MPIM)

organizers: Gunther Cornelissen (UU) and Klaas Landsman (RU)

**Satelite Conference at The Geometric Langlands Program (7-11 July 2008)
**

*July 7th, 2008*

Satelite Conference at The Geometric Langlands Program from 7 Jul 2008 through 11 Jul 2008.

We intend to bring together leading mathematicians working on the Geometric Langlands Program. The GLP has deep connections with Number Theory, Algebraic Geometry and with subjects from mathematical physics such as Quantization and Conformal Field Theory. Internationally the subject has quickly become a major theme bridging between these fields. The proposed workshop brings together various research communities in pure mathematics and mathematical physics in the Netherlands and intends to promote the GLP as a unifying research theme.

Scientific coordinators: E. Frenkel (University of California, Berkeley, USA), G. Heckman (Radboud University Nijmegen, Netherlands), E.J.N. Looijenga (Universiteit Utrecht, Netherlands), E.M. Opdam (UvA, Netherlands).

**Satelite Conference Algebraic Geometry (june 30 – july 4)
**

*June 30th, 2008*

Satelite Conference Algebraic Geometry from 30 Jun 2008 through 4 Jul 2008 at the Lorentz Center

Scientific coordinators: E. Looijenga (Utrecht Univ., The Netherlands), B. Edixhoven (Leiden Univ., The Netherlands), G. van der Geer (Amsterdam Univ., The Netherlands)

**Talks Losev on 24 and 25 june
**

*June 25th, 2008*

Andrey Losev is visiting Amsterdam, and he is going to give two talks:

– Tuesday, June 24, 11:00-13:00, room P0.18, Topological quantum mechanics and higher structures in Morse theory

– Wednesday, June 25, 11:00-13:00, room P0.18, Berkovits superstring as a topological string (towards the third superstring revolution)

Both seminars will take place at the KdVI, Plantage Muidergracht 24, 1018TV Amsterdam. Visit is supported by the NwoRussian cooperation on Geometry and Singularity Theory in Mathematical Physics.

**Talk Sedykh on real global singularity theory
**

*June 24th, 2008*

Tuesday, 14.00-15.00 in room 611 of the Mathematics Institute in Utrecht, there will be another session of the Geometry and Topology seminar.

Speaker: V.Sedykh (Moscow)

Title: On some problems of real global singularity theory

Abstract: Let M and N be smooth closed manifolds of dimensions m and n, respectively, with n greater or equal to m. Consider stable smooth mappings from M to N having only singularities of corank 1. We find a complete system of universal linear relations between the Euler characteristics of the manifolds of multi-singularities of mappings under consideration. As an application, we obtain multidimensional generalizations of the Bose theorem on supporting circles of a plane curve.

Visit is supported by the NwoRussian cooperation on Geometry and Singularity Theory in Mathematical Physics.

**Talk Mueger : Modular Categories
**

*June 23rd, 2008*

You are cordially invited to the Seminar Quantum Groups and Applications

Time: June 23, 10:30-12:30

Location: Room D.3.17 in the D building on Nieuwe Achtergracht 129.

Title: Modular Categories

Speaker: Michael Mueger

Roland van der Veen

**Educational Week on Noncommutative Integration
**

*June 9th, 2008*

In this Educational Week some aspects of noncommutative integration theory associated with von Neumann algebras will be discussed, as well as some of its applications.

**Oratie Erik Koelink
**

*June 5th, 2008*

Locatie: Radboud Universiteit, Academiezaal Aula, Comeniuslaan 2

Tijdstip: 15:45

**GQT-Colloquium
**

*May 30th, 2008*

For the program, see

**the colloquium website**.

**Promotie Oliver Lorscheid
**

*May 28th, 2008*

Titel: “Toroidal automorphic forms for function fields”

**MATH-PHYS SEMINAR DAY
**

*May 23rd, 2008*

Friday May 23, Universiteit Utrecht, Minnaert buidling, MIN 401

14:00 : **Graeme Segal (Oxford U.)** *Noncommutative Geometry and Quantum Field Theory.*

15:00 : Coffee break

15:30 : **Christoph Schweigert (Hamburg U.)** *Bundle Gerbes and Surface Holonomy.*

16:30 : Drinks

**Promotie Rogier Swierstra
**

*April 28th, 2008*

Titel: “Moduli spaces of cubic hypersurfaces through a period map”

**GQT-Colloquium
**

*March 28th, 2008*

**Speakers**

**Gunther Cornelissen** (U Utrecht)

*Riemann surfaces and spectral triples*

I will show how to associate to a compact hyperbolic Riemann surface a finite-dimensional noncommutative Riemannian geometry (a.k.a. finitely summable spectral triple), such that the zeta functions on the noncommutative side capture the complex structure of the Riemann surface. The construction passes via Schottky uniformization and can be seen as a reformulation of an ergodic rigidity theorem a la Mostow in terms of spectral triples. (joint work with Matilde Marcolli, arxiv:0708.0500)

**Duco van Straten** (U Mainz)

*Classical and Quantum integrability*

In the talk I will discuss the following question: Given a classsical integrable system defined by n Poisson commuting polynomials, can one find commuting \hbar-differential operators whose symbols are the given polynomials?

**Markus Reineke** (U Wuppertal):

*Poisson automorphisms and quiver moduli*

We discuss a factorization problem for Poisson automorphisms of a formal plane, which turns out to involve invariants for moduli spaces of quiver representations. This factorization problem appears in recent work of Kontsevich and Soibelman on Donaldson-Thomas invariants of noncommutative Calabi-Yau manifolds. We sketch a proof involving quiver realizations of quantized Kac-Moody algebras.

Location: Linnaeus building, zaal Lin4

**Schedule**

10:45: Coffee and Tea

11:00: G. Cornelissen

12:00: Uitreiking scriptieprijs door W.v.d. Kallen

aansluitend: Jozef Steenbrink met medelingen namens de directeur

14:00: D.v.Straten

15:00: Coffee and tea

15:15: M. Reineke

16:15- : Reception in the Huygens building

**Polynomial Mappings: Algebra, Computation and Topology: Febuary 11 and 12, 2008
**

*February 11th, 2008*

Workshop Polynomial Mappings: Algebra, Computation and Topology

Febuary 11 and 12, 2008 at the Huygens Building, Radboud University Nijmegen (The Netherlands)

These 2 days meeting will concentrate on new methods of algorithmic methods in the geometry and topology of polynomial mappings, both local and global. Special attention will be given to topics as behaviour at infinity, the structure of the bifurcation diagram, monodromy around a given stratum, mixed Hodge structures of fibres, algebraic coumputation of topological invariants, Cohen Macaulay modules, Lie algebras of algebraic varietes and singularities, geometry of quadratic mappings and various versions of Keller Jacobian conjecture.

**Oratie Erik van den Ban
**

*February 8th, 2008*

16.15 uur, Academiegebouw Universiteit Utrecht

**GQT-Colloquium, University of Utrecht, Minnaert building room 211
**

*February 1st, 2008*

**Schedule**

11:15-12:15 Vladimir Kazakov, ENS, Paris VI:

Integrable quantum (super)spin chains and discrete classical dynamics.

12:15 – 13:30 Lunch

13:30 – 14:30 Erik Koelink, RU, Nijmegen:

Quantum groups and the quantum group analogue of SU(1,1).

14:30 – 14:40 Dirk Siersma: News from the GQT board.

14:40 – 15:00 Coffee & Tea.

15:00 – 16:00 Nick Dorey, DAMTP, Cambridge:

Integrability and the AdS/CFT correspondence.

16:00 – ?? Drinks

**Abstracts**

**Vladimir Kazakov**, ENS, Paris VI

*Integrable quantum (super)spin chains and discrete classical dynamics. *

We review a discrete classical dynamics approach to the integrable quantum (super)spin chains. It takes a different venue from the well known algebraic Bethe ansatz but it also allows to go all the way from the definition of the R-matrix to the final system of nested Bethe equations. The intermediate steps include the derivation of the determinant Bazhanov-Reshetikhin formula and the associated integrable discrete bilinear Hirota equation describing the quantum fusion of representations, the solution of this equation by the Backlund transformation and the general formulas for transfer-matrices in terms of Baxters Q-functions. The method looks especially useful in the case of supergroups where the new bilinear relations among Q-functions are observed.

**Erik Koelink**, RU, Nijmegen

*Quantum groups and the quantum group analogue of SU(1,1). *

Quantum groups originated in the 1980ies from different perspectives. It took quite some time before a satisfactory general theory for non-compact quantum groups was established. A general theory on the level of operator algebras for quantum groups has been introduced in 2000 and 2003 by Kustermans and Vaes. We review their definition and main results, and we consider the example of the quantum group analague of the normalizer of SU(1,1) in SL(2,C).

**Nick Dorey**, DAMTP, Cambridge

*Integrability and the AdS/CFT correspondence. *

I will review recent progress towards a solution of N=4 SUSY Yang-Mills theory in the planar limit and related developments in the dual string theory on AdS_5 x S5.

**Workshop on McKay correspondence for symplectic resolutions (following Bezrukavnikov-Kaledin)
**

*January 25th, 2008*

(January 25-26, joint with the group of H. Esnault and E. Viehweg, University Duisburg-Essen and M. Lehn, Universtiy Mainz) The aim of the Workshop is to understand the proof, due to Bezrukavnikov and Kaledin (McKay equivalence for symplectic resolutions of quotient singularities, arXiv:math/0401002), of a higher dimensional generalization of the so called McKay correspondence. This proof uses a rather large variety of ideas, so we hope that the proof itself might be as interesting as the result.

**Speaker Maxim Kazarian
**

*January 23rd, 2008*

Maxim Kazarian (Steklov Mathematical Institute, Moscow) will his second talk in the geometry-topology seminar in Utrecht on wednesday january 23 : 14.00-15.00 room 611B Math Institute.

This talk is a continuation of his lecture on wednesday january 23

Title: Moduli spaces, Hurwitz numbers, and integrable hierarchies (2).

Abstract: see announcement for janary 16

**Speaker Maxim Kazarian
**

*January 16th, 2008*

Maxim Kazarian (Steklov Mathematical Institute, Moscow) visits the Department of Mathematics of Utrecht University from january 9 until february 2, 2008. He will give a series of 2 talks in the geometry-topology seminar in Utrecht:

wednesday january 16 : 14.00-15.00 room 611B Math Institute

wednesday january 23 : 14.00-15.00 room 611 B Math Institute

**Title**: Moduli spaces, Hurwitz numbers, and integrable hierarchies.

**Abstract**: The famous ELSV (Eckedah-Lando-Shapiro-Vainstein) formula relates two theories: the Hurwitz theory of enumerating ramified coverings of a sphere and intersection theory on the moduli spaces of curves. It provides on of the most natural and straightforward explanation of the relationship between intersection theory on moduli spaces and integrable hierarchies discovered by physicists. Starting from the ELSV formula, we derive a number of new equations on the generating functions for Hodge integrals over the moduli space of complex curves. This gives a new simple and uniform treatment of certain known results on Hodge integrals like Witten’s conjecture, Virasoro constrains, Faber’s $\l_g$-conjecture etc. Among other results we show that a properlyarranged generating function for Hodge integrals satisfies the equations of the KP hierarchy.

**Framework** : NWO-RFBR-Project : Geometry and Singularity Theory in Mathematical Physics