# Talk

Talks and seminars, possibly part of a conference or series.

## New guests at the MPIM

Posted in
Speaker:
Kevin Destagnol, Julie Desjardins, Taiwang Deng
Date:
Thu, 2017-09-28 14:00 - 15:00
Location:
MPIM Lecture Hall
Parent event:
MPI-Oberseminar

## A categorical approach to universal knot invariants

Posted in
Speaker:
Danica Kosanovic
Affiliation:
MPIM
Date:
Mon, 2017-09-25 16:30 - 18:00
Location:
MPIM Lecture Hall
Parent event:
MPIM Topology Seminar

## tba

Posted in
Speaker:
Joao Nuno Mestre
Affiliation:
MPIM
Date:
Wed, 2017-10-25 10:30 - 12:00
Location:
MPIM Lecture Hall

## Surface systems of links and refined triple linking numbers

Posted in
Speaker:
Mark Powell
Affiliation:
Durham U.
Date:
Mon, 2017-09-18 16:30 - 18:00
Location:
MPIM Lecture Hall
Parent event:
MPIM Topology Seminar

A surface system for a link in the 3-sphere is a collection of Seifert surfaces for the components of the links, that intersect one another transversally and in at most triple points.  The intersections are thought of as oriented manifolds.  Given two links with the same pairwise linking numbers, do they admit homeomorphic surface systems?

## tba

Posted in
Speaker:
Mark David Penney
Affiliation:
Oxford/MPIM
Date:
Wed, 2017-10-18 10:30 - 12:00
Location:
MPIM Lecture Hall

## Topological Twists of Factorization Algebras

Posted in
Speaker:
Chris Elliott
Affiliation:
IHES
Date:
Mon, 2017-10-23 16:30 - 18:00
Location:
MPIM Lecture Hall
Parent event:
MPIM Topology Seminar

The idea of topologically twisting a supersymmetric field theory was introduced in the physics literature in order to generate interesting new examples of topological field theories.  The idea is very general, but systematically realising the examples it produces is not always possible using mathematical models for topological field theory (such as Atiyah-Segal's functorial field theory, or the theory of E_n-algebras).  In this talk I'll explain what it means to twist a supersymmetric field theory in the factorization algebra framework devel

## New guests at the MPIM

Posted in
Speaker:
Andrea Conti, Yang Cao, Paolo Aceto
Date:
Thu, 2017-09-21 14:00 - 15:00
Location:
MPIM Lecture Hall
Parent event:
MPI-Oberseminar

## Harmonic maps between Riemannian manifolds

Posted in
Speaker:
Maria Bertozzi
Affiliation:
U. Bonn
Date:
Tue, 2017-09-26 10:00 - 11:00
Location:
MPIM Seminar Room
Parent event:
Extra talk

## Algebraic K-theory of infinite products via Grayson's binary complexes

Posted in
Speaker:
Christoph Winges
Affiliation:
MPIM
Date:
Thu, 2017-09-14 14:00 - 15:00
Location:
MPIM Lecture Hall
Parent event:
MPI-Oberseminar

## BV formalism of T-duality geometry

Posted in
Speaker:
Noriaki Ikeda
Affiliation:
Ritsumeikan University
Date:
Wed, 2017-09-13 10:30 - 12:00
Location:
MPIM Seminar Room

A BV formalism is not only a fundamental framework of quantum field theory, but also appears in a variety of fields of mathematics and physics as an universal structure. After we prepare BV-geometry and notion of so called NS fluxes and T-duality, we reformulate geometry of T-duality by the BV-AKSZ formalism based on supergeometry. Moreover we explain that extended T-duality recently proposed in physics is also formulated and unified by this formalism.

## Variations of semi-infinite Hodge structures, quantum master equation on cyclic cochains, Feynman transforms and cohomological field theories

Posted in
Speaker:
S. Barannikov
Affiliation:
Paris-VII
Date:
Tue, 2017-09-19 14:00 - 15:00
Location:
MPIM Lecture Hall
The purpose of the talk is the description of the constructions of cohomology classes of the compactified moduli spaces of curves via summation over graphs, described earlier in the works of the speaker. One construction is related with solutions to the quantum master equation on cyclic cochains,  and another is related with the variations of semi-infinite Hodge structures of Calabi-Yau type. The Feynman transforms control the properties of the constructed cohomology classes.

## On Cayley and Langlands type correspondences for Higgs bundles

Posted in
Speaker:
Laura Schaposnik
Affiliation:
U Illinois at Chicago
Date:
Wed, 2017-10-11 10:30 - 12:00
Location:
MPIM Lecture Hall

The Hitchin fibration is a natural tool through which one can understand the moduli space of Higgs bundles and its interesting subspaces (branes). After reviewing the type of questions and methods considered in the area, we shall dedicate this talk to the study of certain branes which lie completely inside the singular fibres of the Hitchin fibrations.

## The Khovanov space and generalizations

Posted in
Speaker:
Andrew Lobb
Affiliation:
U. Durham/MPIM
Date:
Mon, 2017-09-11 16:30 - 18:00
Location:
MPIM Lecture Hall
Parent event:
MPIM Topology Seminar

A quantum knot cohomology is a knot invariant recovering a quantum knot polynomial as its Euler characteristic.  Sometimes these cohomologies are the usual singular cohomologies of spaces which are themselves knot invariants.  The first example is due to Lipshitz and Sarkar: the Khovanov space.  I'll tell you why you might care about this if you're only interested in low-dimensional topology.  I'll also sketch the construction, aiming to keep it understandable, and point to some generalizations.  No knowledge assumed.  This is join

## Formality theorem and Kontsevich-Duflo theorem for Lie pairs

Posted in
Speaker:
Hsuan-Yi Liao
Affiliation:
Penn State
Date:
Wed, 2017-09-27 10:30 - 12:00
Location:
MPIM Seminar Room

A Lie pair $(L,A)$ consists of a Lie algebroid $L$ together with a Lie subalgebroid $A$. A wide range of geometric situations can be described in terms of Lie pairs including complex manifolds, foliations, and manifolds equipped with Lie algebra actions. We establish the formality theorem for Lie pairs. As an application, we obtain Kontsevich-Duflo type theorems for Lie pairs. In this talk, I'll start with the case of $\mathbf{g}$-manifolds, i.e., smooth manifolds equipped with Lie algebra actions.

## New guests at the MPIM

Posted in
Speaker:
Augusto Ritter Stoffel (MPIM), Haoyu Hu (University of Tokyo/MPIM)
Date:
Thu, 2017-09-07 14:00 - 15:00
Location:
MPIM Lecture Hall
Parent event:
MPI-Oberseminar

## On semiconjugate rational functions

Posted in
Speaker:
Fedor Pakovich
Affiliation:
Ben Gurion University of the Negev/MPI
Date:
Tue, 2017-09-12 14:00 - 15:00
Location:
MPIM Lecture Hall

Let A and B be rational functions on the Riemann sphere. The function B is
said to be semiconjugate to the function A if there exists a non-constant rational
function X such that A\circ X= X\circ B  (*).

The semiconjugacy condition generalises both the classical conjugacy relation and
the commutativity condition. In the talk we present a description of solutions of
functional equaton (*) in terms of orbifolds of non-negative Euler characteristic on
the Riemann sphere, and discuss numerous relations of this equation with complex
dynamics and number theory.

## Exotic Poisson summation formulas on the real line

Posted in
Speaker:
Danylo Radchenko
Affiliation:
ICTP Trieste/MPI
Date:
Tue, 2017-09-05 14:00 - 15:00
Location:
MPIM Lecture Hall

A crystalline measure is a measure whose support is a discrete closed set,
and whose Fourier transform is also a measure with this property. A
generalized Dirac comb is always crystalline, and all other crystalline
measures are called exotic. I will describe a recent construction of a
continuous family of exotic crystalline measures that uses weakly
holomorphic modular forms on the Hecke group.
The talk is based on a joint work with Maryna Viazovska.

## The Kontsevich integral revisited

Posted in
Speaker:
JungHwan Park
Affiliation:
MPIM
Date:
Mon, 2017-09-04 16:30 - 17:30
Location:
MPIM Seminar Room
Parent event:
MPIM Topology Seminar

## tba

Posted in
Speaker:
Katie Gittins
Affiliation:
Université de Neuchatel/MPI
Date:
Thu, 2017-10-19 16:30 - 17:30
Location:
MPIM Lecture Hall

## On Habiro’s 3-manifold/knot invariants

Posted in
Speaker:
Peter Feller
Affiliation:
MPI
Date:
Mon, 2017-08-28 16:30 - 18:00
Location:
MPIM Lecture Hall
Parent event:
MPIM Topology Seminar
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