## Upcoming conferences & activities

## Conference on "Higher Homotopy Algebras in Topology", May 9 - 10, 2019

**Conference on "Higher Homotopy Algebras in Topology", May 9 - 10, 2019**

Algebras up to homotopy, or homotopy algebras, such as $A_\infty$, $C_\infty$, $E_\infty$ and $L_\infty$, play an increasingly important role in many areas of mathematics and physics, like topology, mathematical physics, and deformation theory. Let us mention a few examples of interest. Homotopy Lie algebras, also known as $L_\infty$-algebras, have been essential in Kontsevich's proof of deformation quantization. In algebraic topology, $C_\infty$ and $L_\infty$-algebras arise as structures governing the rational homotopy type of spaces, and $E_\infty$-(co)algebras naturally appear as an algebraic structure on infinite loop spaces and on the singular (co)chains of any space. Recent advances in this line include the use of higher homotopy algebras to model all sorts of interesting spaces, such as mapping spaces, sections of fiber bundles, configuration spaces, among many others.

This mini-conference focuses on the most recent developments and applications of homotopy algebras in topology.

Organizers

Felix Wierstra (MPIM Bonn)

#### Provisory list of speakers:

Ricardo Campos (Université de Montpellier)

Joana Cirici (Universitat de Barcelona)

Vladimir Dotsenko (Trinity College Dublin)

Benoit Fresse (Université de Lille)

Najib Idrissi (Université Paris Diderot)

Pascal Lambrechts (Université catholique de Louvain-la-Neuve)

Aniceto Murillo (Universidad de Malaga)

Fernando Muro (Universidad de Sevilla)

* to be confirmed.

## Conference on "Enumerative Arithmetic and the Cohen–Lenstra Heuristics", June 3 - 7, 2019

**Conference on "Enumerative Arithmetic and the Cohen–Lenstra Heuristics", June 3 - 7, 2019**

#### Organizers

#### Selected invited speakers:

* to be confirmed

## Arbeitstagung 2019 on Geometry

#### Arbeitstagung 2019 on Geometry, July 8 - 12, 2019

#### Organizers

W. Ballmann, U. Hamenstädt, and M. Kapovich

#### Local Organizers

#### Speakers

Gelander, Tsachik (The Weizmann Institute of Science)

Hein, Hans-Joachim (Fordham University)

Kleiner, Bruce (New York University)

Markovic, Vladimir (Caltech)

Song, Antoine (Princeton University)

#### Minicourses by

Gelander, Tsachik (The Weizmann Institute of Science)

Kleiner, Bruce (New York University)

In addition to the scheduled talks, 6 more lectures will be determined in the traditional Arbeitstagung way by open discussion during the meeting.

## Conference on "Geometry, integrability and Moduli", July 29 - August 2, 2019

**Conference on "Geometry, integrability and Moduli" July 29 - August 2, 2019**

This is a conference in honor of Motohico Mulase's 65th birthday. It will cover recent advances around the following themes

- Quantization of moduli spaces, in particular the Hitchin moduli space of Higgs bundles
- Gromov-Witten theory, Frobenius manifolds, integrable hierarchies, cohomological field theories
- Geometry of quiver varieties, wall-crossing phenomena
- Mirror symmetry, topological string theory, quantum invariants of 3-manifolds
- Topological recursion, quantum curves, and application to geometry and enumerative problems (Hurwitz theory, random matrix theory, ribbon graphs)

Connections between these fields are apparent from the physics perspective and research is trying to make rigorous sense of these relationships. Encouraging the exchanges between mathematicians and theoretical physicists will thus be an important dimension of the conference. More details available soon.

#### Organizers

Olivia Dumitrescu (Central Michigan University)

Steven Rayan (University of Saskatchewan)

Don Zagier (MPIM Bonn)

#### Provisory list of speakers:

Ron Donagi (University of Pennsylvania)

Bertrand Eynard (IPHT CEA Saclay)

Tamas Hausel (IST Austria)

Laura Fredrickson (Stanford)

Kenji Fukaya (Stony Brook)

Hiroshi Iritani (Kyoto University)

Maxim Kontsevich (IHES)

Melissa Liu (Columbia University)

Yuri Manin (MPIM Bonn)

Marcos Mariño (Université de Genève)

Hannah Markwig (Tübingen Universität)

Takuro Mochizuki (RIMS Kyoto)

Hiraku Nakajima (IPMU Tokyo)

Andrew Neitzke (The University of Texas at Austin)

Tony Pantev (University of Pennsylvania)

Yan Soibelman (Kansas State University)

## Workshop on 4-manifolds, September 16 - 20, 2019

**Workshop on 4-manifolds, September 16 - 20, 2019**

#### Organizers

Jeffrey Meier (University of Georgia)

Arunima Ray (MPIM Bonn)

#### Confirmed Speakers:

Robert Gompf (UT Austin)

Sergei Gukov (Caltech)

András Juhász (Oxford)

Du Pei (Caltech)

Lisa Piccirillo (UT Austin)

Juanita Pinzón-Caicedo (North Carolina State University/MPIM Bonn)

Mark Powell (Durham)

Rob Schneiderman (CUNY)

Hannah Schwartz (Bryn Mawr/MPIM Bonn)

Laura Starkston (UC Davis)

András Stipsicz (Alfred Renyi)

Alex Zupan (University of Nebraska Lincoln)

## Upcoming Talks

Abstracts of upcoming talks at the MPIM. For an overview see also the calendar.

## "What is...?" seminar

## Recent developments in Quantum Topology

We will review the basics of quantum topology such as the colored Jones polynomial of a knot, its standard conjectures relating to asymptotics, arithmeticity and modularity, as well as the recent quantum hyperbolic invariants of Kashaev et al, their state-integrals and their

structural properties. The course is aimed to be accessible by graduate students and young researchers.

## Lecture course by Stavros Garoufalidis

We will review the basics of quantum topology such as the colored Jones polynomial of a knot, its standard conjectures relating to asymptotics, arithmeticity and modularity, as well as the recent quantum hyperbolic invariants of Kashaev et al, their state-integrals and their

structural properties. The course is aimed to be accessible by graduate students and young researchers.

## Vertex Operator Algebras and Modular Forms

Time: Tuesdays, 4.30 - 6 pm

Place: MPIM Lecture Hall, Vivatsgasse 7

First lecture: on April 2, 2019, end on July 2

## Canonical Lifts in Families and delta-structures

Serre-Tate proved in the 60's that an ordinary abelian variety E over a finite field k can be canonically lifted to an ordinary abelian variety over the Witt vectors of k. Expressed in terms of the moduli stack M_ord of ordinary abelian schemes, this is precisely a universal lifting property with respect to the Witt vectors (of finite fields).

## Homology of the little disks operad

## Distinguished cycles on hyperKaehler varieties

The aim of this talk is to give an overview of various subrings of the Chow ring of hyperKaehler varieties, which like the Beauville-Voisin ring conjecturally inject in cohomology via the cycle class map. I will give examples of hyperKaehler varieties for which such injectivity statements are known to be true and I will explain how these various subrings relate to each other (conjecturally and in examples). I will also concomitantly draw the parallel picture for abelian varieties. This is based on works with Lie Fu, Robert Laterveer and Mingmin Shen.

## Families of surfaces of general type

The purpose of this talk is to give a very elementary introduction to the problem of classifying surfaces of general type. I will particularly discuss the case when the surfaces are defined over an algebraically closed field of characteristic p>0, the pathologies that appear in this case in comparison to the characteristic zero case and possible ways to deal with them. The talk will be accessible to a general mathematical audience.

## On elliptic Toda systems

Toda systems are important examples of integrable systems, and we consider the version using the Laplacian on the plane. They are generalizations of the Liouville equation to simple Lie algebras. As such, they are related to 2-dimensional conformal geometry and harmonic maps.

In this talk, we will discuss the classification of solutions to such Toda systems and the quantization result on their total masses. Such total masses have applications to the local blowup analysis of the mean field equations.

## What is a Lie groupoid

## Mathematical events in Bonn

##### Bonn Mathematics Calendar

All mathematical events in Bonn are listed in the Bonn Mathematics Calendar. For directions see the map.

##### University Calendar

All lectures and courses at Bonn University can be found in the university calendar.

## Recurring seminars, series and courses

Detailed list of recurring seminars, series of talks, and courses or lectures comprising multiple talks. For an overview see also the calendar.

## Friedrich Hirzebruch Lecture

The annual Friedrich Hirzebruch Lecture is a series of lectures started in 2007 on the occasion of the 80th birthday of Prof. Friedrich Hirzebruch. The lectures address a general audience and aim at illustrating the relation between mathematics and art, society and other fields.

## MPI-Oberseminar

The Oberseminar is a very long running seminar at MPI (‘Ober‘ standing for 'upper'). Its idea is that the guests of the MPI speak in this seminar (hopefully early in their stay) and get the chance to explain their work to the other guests.

## Representation theory learning seminar

## Extra talk

## IMPRS Minicourse

## Seminar on Algebra, Geometry and Physics

## Seminar Algebraic Geometry (SAG)

## Higher Differential Geometry Seminar

## Archived Events

To narrow the list of events displayed please select year and event type or fill the search fields, then press *Apply*.

## Conference on "Elementare und Analytische Zahlentheorie (ELAZ)", September 3 - 7, 2018

**Conference on "Elementare und Analytische Zahlentheorie (ELAZ)"**

**September 3 - 7, 2018**

### Organizers

Kathrin Bringmann (Universität zu Köln)

Stephan Ehlen (Universität zu Köln)

Pieter Moree (MPIM Bonn)

## MPI-Oberseminar

The Oberseminar is a very long running seminar at MPI (‘Ober‘ standing for 'upper'). Its idea is that the guests of the MPI speak in this seminar (hopefully early in their stay) and get the chance to explain their work to the other guests.

## Friedrich Hirzebruch Lecture

The annual Friedrich Hirzebruch Lecture is a series of lectures started in 2007 on the occasion of the 80th birthday of Prof. Friedrich Hirzebruch. The lectures address a general audience and aim at illustrating the relation between mathematics and art, society and other fields.

## Workshop on 4-manifolds, September 16 - 20, 2019

**Workshop on 4-manifolds, September 16 - 20, 2019**

#### Organizers

Jeffrey Meier (University of Georgia)

Arunima Ray (MPIM Bonn)

#### Confirmed Speakers:

Robert Gompf (UT Austin)

Sergei Gukov (Caltech)

András Juhász (Oxford)

Du Pei (Caltech)

Lisa Piccirillo (UT Austin)

Juanita Pinzón-Caicedo (North Carolina State University/MPIM Bonn)

Mark Powell (Durham)

Rob Schneiderman (CUNY)

Hannah Schwartz (Bryn Mawr/MPIM Bonn)

Laura Starkston (UC Davis)

András Stipsicz (Alfred Renyi)

Alex Zupan (University of Nebraska Lincoln)

## Conference on "Geometry, integrability and Moduli", July 29 - August 2, 2019

**Conference on "Geometry, integrability and Moduli" July 29 - August 2, 2019**

This is a conference in honor of Motohico Mulase's 65th birthday. It will cover recent advances around the following themes

- Quantization of moduli spaces, in particular the Hitchin moduli space of Higgs bundles
- Gromov-Witten theory, Frobenius manifolds, integrable hierarchies, cohomological field theories
- Geometry of quiver varieties, wall-crossing phenomena
- Mirror symmetry, topological string theory, quantum invariants of 3-manifolds
- Topological recursion, quantum curves, and application to geometry and enumerative problems (Hurwitz theory, random matrix theory, ribbon graphs)

Connections between these fields are apparent from the physics perspective and research is trying to make rigorous sense of these relationships. Encouraging the exchanges between mathematicians and theoretical physicists will thus be an important dimension of the conference. More details available soon.

#### Organizers

Olivia Dumitrescu (Central Michigan University)

Steven Rayan (University of Saskatchewan)

Don Zagier (MPIM Bonn)

#### Provisory list of speakers:

Ron Donagi (University of Pennsylvania)

Bertrand Eynard (IPHT CEA Saclay)

Tamas Hausel (IST Austria)

Laura Fredrickson (Stanford)

Kenji Fukaya (Stony Brook)

Hiroshi Iritani (Kyoto University)

Maxim Kontsevich (IHES)

Melissa Liu (Columbia University)

Yuri Manin (MPIM Bonn)

Marcos Mariño (Université de Genève)

Hannah Markwig (Tübingen Universität)

Takuro Mochizuki (RIMS Kyoto)

Hiraku Nakajima (IPMU Tokyo)

Andrew Neitzke (The University of Texas at Austin)

Tony Pantev (University of Pennsylvania)

Yan Soibelman (Kansas State University)

## Harmonic Morphisms from Lie Groups and Symmetric Spaces - Some Existence Theory

The study of harmonic morphisms in the 3-dimensional Euclidean space

goes back to a paper of Jacobi from 1848. This was then introduced into

the setting of Riemannian geometry, in the late 1970s by Fuglede and

Ishihara, independently. A harmonic morphism $\phi : (M, g)\to (N, h)$

between two Riemannian manifolds is a map that pulls back real-valued

## Coffee break

## Minicourse 2

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