Topos à l’IHES

The concept of topos was introduced by A. Grothendieck during his Séminaire de Géométrie Algébrique du Bois-Marie, which took place at the IHES in the early sixties. The original motivation was that of defining a general notion of space on which one could define cohomological invariants in the algebro-geometric setting needed for proving the Weil's conjectures. In spite of this quite specific technical motivation, the notion of topos appeared at the very beginning as defining a new conception of space, capable of unifying the continuous and the discrete in an harmonious marriage: in the words of Grothendieck "Un lit si vaste en effet (telle une vaste et paisible rivière très profonde…), que “tous les chevaux du roi y pourraient boire ensemble…". "
 
In the following years, new perspectives on the notion on topos emerged. According to Lawvere and Tierney, a topos can be considered not only as a generalized space but as a mathematical universe within which one can carry out most familiar set-theoretic constructions, but which also, thanks to the inherent ‘flexibility' of the notion of topos, can be profitably exploited to construct 'new mathematical worlds' having particular properties. On the other hand, the theory of classifying toposes allows to regard a Grothendieck topos as a suitable kind of first-order theory modulo Morita-equivalence. Toposes have also been proved effective in studying dualities and establishing ‘bridges’ across different mathematical theories with a related semantic content.  
 
The conference aims to illustrate the fruitfulness and wide-ranging impact of the notion of topos, by featuring presentations on new theoretical advances in the subject (including the theory of higher toposes) as well as on applications of toposes in different fields such as number theory, algebraic geometry, logic, functional analysis, topology, mathematical physics and computer science. The conference is preceded by a two-day introductory mini-course for the benefit of students and mathematicians who are not already familiar with topos theory.

Scientific committee : O. CARAMELLO*, P. CARTIER, A. CONNES, S. DUGOWSON, A. KHELIF

23-24 November : Tutorials by: Olivia CARAMELLO and André JOYAL

25-27 November : Invited speakers :

Mathieu ANEL (University Paris-Diderot)
Luca BARBIERI-VIALE (Università degli Studi di Milano)
Jean BÉNABOU (University Paris 13)
Caterina CONSANI (Johns Hopkins University, Baltimore)
Thierry COQUAND (University of Göteborg)
Simon HENRY (Radboud University, Nijmegen)
André JOYAL (Université du Quebec, Montréal)
Mike PREST (University of Manchester)
Urs SCHREIBER (Eduard Čech Institute for Algebra, Geometry and Physics, Prague)
Carlos SIMPSON (University of Nice-Sophia-Antipolis) 
Michel VAQUIÉ (University Paul Sabatier, Toulouse)

25 & 27 November: Short Communications Speakers

Ingo BLECHSCHMIDT (University of Augsburg)
Matias DATA (Universidad de Buenos Aires)
Jonas FREY (Copenhagen University)
Camell KACHOUR
Guilherme Frederico LIMA de CARVALHO e SILVA (University of Cambridge)
Pietro POLESELLO (Universita di Padova)
David ROBERTS (University of Adelaide)
Anna Carla RUSSO (University of Salerno & Université Paris-Diderot)
Alex SIMPSON (University of Ljubljana)
Zoran  SKODA (University of Hradec Kralové)
Christopher TOWNSEND (Royal Bank of Canada)

* holder of a fellowship "L'Oréal-Unesco for Women in Science" which supports the conference
 

The non-official website of the conference  ­(maintained by S. Dugowson)
contains further materials provided by the speakers
­in connection with their talks and edited versions of the videos of the tutorials.

Nonlinear Waves 2016 : June Conference

List of speakers includes:

      Thomas ALAZARD (ENS Paris)
      Valeria BANICA (Université d'Evry Val d'Essonne)
      Diego CORDOBA (ICMAT)
      Mihalis DAFERMOS (University of Cambridge)
      Camillo DE LELLIS (Universität Zürich)
      Benjamin DODSON (Johns Hopkins University)
      Patrick GERARD (Université Paris-Sud)
      Pierre GERMAIN (Courant Institute of Mathematics)
      Cécile HUNEAU (ENS Paris)
      Alexandre IONESCU (Princeton University)
      Robert JERRARD (University of Toronto)
      Thomas KAPPELER (Universität Zürich)
      Rowan KILLIP (UC Los Angeles)
      Michal KOWALCZYK (Universidad de Chile)
      David LANNES (Université de Bordeaux 1)
      Andrew LAWRIE (University of California, Berkeley)
      Enno LENZMANN (Universität Basel)
      Andrea NAHMOD (University of Massachusetts, Amherst)
      Fabio PUSATERI (Princeton University)
      Benjamin SCHLEIN (Universität Zürich)
      Christopher SOGGE (Johns Hopkins University)
      Vlad VICOL (Princeton University)
      Hatem ZAAG (Université Paris 13)

Organising Committee:

      Thomas DUYCKAERTS (Université Paris 13)
      Frank MERLE (Université de Cergy-Pontoise & IHÉS)
      Jérémie SZEFTEL (Université Pierre et Marie Curie)

Crédit photographique: © CNRS Photothèque
RAJAU Benoît (UMR7538 – Laboratoire de physique des lasers (LPL), VILLETANEUSE et VRIGNAUD François (UMR6172 – XLIM – LIMOGES)

With the support of

 

Séminaire Grothendieck

SÉMINAIRE GROTHENDIECK

Organisé par : L. Barbieri-Viale, F. Brown, D. Gaitsgory et L. Lafforgue 

Conférenciers :

Yves André (Institut de mathématiques de Jussieu)
Joseph Ayoub (Universität Zürich)
Michael Hopkins (Harvard University)
Moritz Kerz (Universität Regensburg) 

Exposé extra-mathématique :

Céline Pessis (coordinatrice du livre "Survivre et vivre. Critique de la science, naissance de l'écologie")

Présentation et projection d’un film :

"L'espace d'un homme" par  Hervé Nisic

 

 

Journée Statistique et Informatique pour la Science des Données à Paris Saclay

The aim of this workshop is to bring together mathematicians and computer scientists around some talks on recent results from statistics, machine learning and more generally data science research. Various topics in machine learning, optimization, deep learning, optimal transport, inverse problems, statistics and problems of scientific reproducibility will be presented.

Registration is free and open to January 20, 2020.

Organised by: Alexandre Gramfort (INRIA) and Thanh Mai Pham NGOC (LMO Orsay)

Invited speakers:

Sarah Cohen-Boulakia (LRI, Paris-Sud)
Victor-Emmanuel Brunel (ENSAE/CREST)
Steve Oudot (INRIA)
Charles Soussen (CentraleSupélec)
Gilles Blanchard (IHES)
Quentin Merigot (Paris-Sud)

Combinatorics and Arithmetic for Physics: special days

Combinatorics and Arithmetic for Physics: special days

The meeting’s focus is on questions of discrete mathematics and number theory with an emphasis on computability. Problems are drawn mainly from theoretical physics (renormalisation, combinatorial physics, geometry) or related to its models.

Computation, based on combinatorial structures (graphs,trees, words, automata, semirings, bases) or classic structures (operators, Hopf algebras, evolution equations, special functions, categories) are good candidates for computer-based implementation and experimentation.

Organised by : Gérard H.E. Duchamp, Maxim Kontsevich, Gleb Koshevoy et Hoang Ngoc Minh

Invited speakers :

Nicolas Behr (Université de Paris, IRIF)
Marc Bellon (LPThE-Sorbonne-Univ., Paris and CNRS)
Pierre Cartier (IHES)
Bérénice Delcroix-Oger (Université de Paris, IRIF)
Gérard Duchamp (IHP and LIPN, Univ. Paris XIII)
Thomas Fernique (CNRS and LIPN, Univ. Paris XIII)
Stéphane Gaubert (INRIA and CMAP, École Polytechnique)
Dima Grigoryev (CNRS Painlevé Lab, Univ. Lille)
Dmitry Gurevich (Valenciennes Univ., France)
Richard Kerner (LPTMC, Sorbonne-Univ., Paris)
Maxim Kontsevich (IHES)
Gleb Koshevoy (ISCP, Moscow)
Annie Lemarchand (LPTMC, Sorbonne-Univ., Paris)
Léon Masurel (LPTMC, Sorbonne-Univ., Paris)
Vincel Hoang Ngoc Minh (Univ. Lille and LIPN, Univ. Paris XIII)
Gabriel Morgado (LPTMC, Sorbonne-Univ., Paris)
Frédéric Patras (LJAD, Univ. Côte d’Azur and CNRS)
Karol A. Penson (LPTMC, Sorbonne-Univ., Paris)
Vincent Rivasseau (LPT, Univ. Paris-Sud, Orsay)
Alan Sokal (University College London and New York University)
Pierre Vanhove (IPhT CEA/Saclay, HSE)

      

Algebraic Structures in Perturbative Quantum Field Theory

—————————————– IMPORTANT INFORMATION ——————————————

Due to the evolution of the health situation related to the Coronavirus epidemic, the conference will finally be totally on line. The Zoom link will be sent in the confirmation mail.

———————————————————————————————————————-

Algebraic Structures in Perturbative Quantum Field Theory
A conference in honour of Dirk Kreimer’s 60th birthday

On the occasion of Dirk Kreimer’s birthday, there will be a special issue of SIGMA on « Algebraic Structures in Perturbative Quantum Field Theory ».

Perturbative quantum field theory is essential for precision calculations of observables measured in experiments like the LHC, and therefore it is crucial for our understanding of the physics of the universe. At the same time, it is an extremely rich source of connections to a wide range of active research areas in mathematics. For example, Feynman integrals give rise to interesting motives and periods in algebraic geometry, their renormalization rests on combinatorial Hopf algebras underlying Feynman graphs, and further relations to noncommutative geometry and the moduli space of tropical curves and outer space have also been discovered.

This growing program keeps expanding in both breadth and depth, and exciting young researchers are entering the field. Now is an opportune time to bring together scientists working on all related aspects, to review old and new connections and to advance the state of the art. Lectures by established scientists will be accompanied by talks from young researchers, including a session dedicated to present and discuss open problems.

Close collaborations between mathematicians and physicists have been absolutely key for this kind of research, and many were initiated by Dirk Kreimer. Throughout his career, he made substantial contributions across these topics and led students and collaborators to the profound mathematical structures in perturbative quantum field theory that we are aware of today. Dirk Kreimer spent a particularly productive time at the IHES, and it is an honour that this workshop takes place in its inspiring and interdisciplinary environment.

Organisers: Erik PANZER (University of Oxford) & Karen YEATS (University of Waterloo)

Invited speakers include:

Ali Assem Mahmoud, University of Waterloo
Marc Bellon, LPTHE (Sorbonne Université)
Marko Berghoff, Humboldt-Universität
Spencer Bloch, University of Chicago
Johannes Blümlein, DESY Zeuthen
Michael Borinsky, Nikhef
David Broadhurst, The Open University
Francis Brown, University of Oxford
Yvain Bruned, University of Edinburgh
Alain Connes, IHES & Collège de France
Andrei Davydychev, Moscow State University
Gérald Dunne, University of Connecticut
Kurusch Ebrahimi-Fard, NTNU Trondheim
Loïc Foissy, Université du Littoral Côte d’Opale
Hadleigh Frost, University of Oxford
John Gracey, University of Liverpool
Martin Hairer, Imperial College London
Ralph Kaufmann, Purdue University
Thomas Krajewski, CPT Aix-Marseille
Dominique Manchon, CNRS & Université Clermont-Auvergne
Lukas NABERGALL, University of Waterloo
Sylvie Paycha, Institut für Mathematik Potsdam
Oliver Schnetz, FAU Erlangen-Nürnberg
Christian Schubert, Universidad Michoacana de San Nicolas de Hidalgo
Matt Szczesny, Boston University
Walter van Suijlekom, Radboud Universiteit Nijmegen
Karen Vogtmann, University of Warwick
Raimar Wulkenhaar, Westfälische Wilhelms-Universität Münster

 

Organized with the support of:

Combinatorics and Arithmetic for Physics: special days

—————————————– IMPORTANT INFORMATION ——————————————

Due to the evolution of the health situation related to the Coronavirus epidemic, the conference will finally be totally on line. The Zoom link will be sent in the confirmation mail.

———————————————————————————————————————-

 

Combinatorics and Arithmetic for Physics: special days

The meeting’s focus is on questions of discrete mathematics and number theory with an emphasis on computability. Problems are drawn mainly from theoretical physics (renormalisation, combinatorial physics, geometry, evolution equations, noncommutative differential equations) or related to its models, but not only.

Computation, based on combinatorial structures (graphs,trees, words, automata, semirings, bases) or classic structures (operators, Hopf algebras, evolution equations, special functions, categories) are good candidates for computer-based implementation and experimentation. »

Organised by : Gérard H.E. Duchamp, Maxim Kontsevich, Gleb Koshevoy et Hoang Ngoc Minh

Updated information (as the Book of Abstracts) can be found there
https://www-lipn.univ-paris13.fr/~duchamp/Conferences/CAP7_2020.html

Schlumberger workshop on Topics in Applied Probability

­
Schlumberger workshop on Topics in Applied Probability
Centre de conférenc­es Marilyn et James Simons
28 mars 2014­­­
­Organisateurs : Josselin Garnier, George Papanicolaou
Conférenciers invités :

­­ Yves Achdou­ (Université Paris VII)
­ Nicolas Champagnat (Université de Lorraine)
François Delarue ­(Université de Nice Sophia-Antipolis)
Sylvie Méléard (Ecole Polytechnique)
Huyên Pham (Université Paris VII)­
Gilles Wainrib ­(Université Paris XIII­)

Statistics/Learning at Paris-Saclay

The aim of this workshop is to bring together mathematicians and computer scientists around some talks on recent results in statistics and machine learning. Various topics will be presented, among which sequential learning, aggregation of estimators, Hidden Markov models, network inference and optimization for machine learning.

Organised by : Sylvain ARLOT

Invited speakers :

Pierre Alquier (ENSAE)
Stéphane Gaiffas (Ecole Polytechnique)
Claire Lacour (Université Paris-Sud)
Odalric-Ambrym Maillard (INRIA – Université Paris-Sud)
Yann Ollivier (CNRS – Université Paris-Sud)
Joseph Salmon (LTCI, CNRS, Télécom ParisTech)

 

 

Computational and statistical trade-offs in learning

COMPUTATIONAL AND STATISTICAL TRADE-OFFS IN LEARNING

Organized by: Sylvain Arlot (Université Paris-Sud, Paris-Saclay), Francis Bach (INRIA Paris), Alain Celisse (Université de Lille 1)

This workshop focuses on the computational and statistical trade-offs arising in various domains (optimization, statistical/machine learning).
This is a challenging question since it amounts to optimize the performance under limited computational resources, which is crucial in the large-scale data context.
One main goal is to identify important ideas independently developed in some communities that could benefit the others.

Speakers :

Pierre Alquier (ENSAE, Paris-Saclay)
Alexandre d'Aspremont (D.I., CNRS/ENS Paris)
Quentin Berthet (DPMMS, Cambridge Univ., UK)
Alain Celisse (Université de Lille 1)
Rémi Gribonval (INRIA, Rennes)
Emilie Kaufmann (CNRS, Lille)
Vianney Perchet (CREST, ENSAE Paris-Saclay)
Garvesh Raskutti (Wisconsin Institute for Discovery, Madison, USA)
Ohad Shamir (Weizmann Institute, Rehovot, Israel)
Silvia Villa (Istituto Italiano di Tecnologia, Genova & MIT, Cambridge, USA)

 

Huawei-IHES Workshop on Mathematical Theories for Information and Communication Technologies

As part of the IHES-Huawei partnership, this one-day workshop is organised by the Huawei's Mathematical and Algorithmic Sciences Lab jointly with IHÉS and aims at creating scientific exchanges around mathematical topics that are essential for the development and innovation of the ICT.

 

Arithmetic and Algebraic Geometry: A conference in honor of Ofer Gabber on the occasion of his 60th birthday

Arithmetic and Algebraic Geometry:

A conference in honor of Ofer Gabber on the occasion of his 60th birthday

List of speakers includes:

     Y. André (CNRS & IMJ-PRG),
     A. Beilinson (University of Chicago),
     B. Bhatt (University of Michigan),
     B. Conrad (Stanford),
     G. Faltings (MPIM),
     D. Gaitsgory (Harvard),
     K. Kato (University of Chicago),
     N. Katz (Princeton),
     M. Kisin (Harvard),
     G. Laumon (Université Paris-Sud),
     G. Lusztig (MIT),
     M. Olsson (UC Berkeley),
     F. Orgogozo (CNRS & École polytechnique),
     L. Ramero (Université de Lille I),
     T. Saito (University of Tokyo),
     P. Scholze (Universität Bonn),
     A. Shiho (University of Tokyo),
     Y. Varshavsky (Hebrew University of Jerusalem),
     A. Vasiu (Binghamton University),
     G. Williamson (University of Sydney),
     W. Zheng (Morningside Center of Mathematics)

Organising Committee:

     A. Abbes (CNRS & IHÉS),
     S. Bloch (University of Chicago),
     L. Illusie (Université Paris-Sud),
     B. Mazur (Harvard)

Organized in partnership with