The purpose of this lecture series is to introduce the audience to basic ideas of specific areas of contemporary pure mathematics. Each lecture shall present an area: where it comes from, where it currently is, where it goes. Lectures will be given by prominent mathematicians twice a year: in the Spring and in the Autumn. Before and after each lecture we will organize reading seminars to prepare the audience for the lecture and to dig further into the topic of the lecture. With the lecturer’s consent, lectures will be recorded, slides and/or lecture notes will be provided if available.

The research school is an introductory meeting to the thematic program “Representation Theory and Noncommutative Geometry” to be held at IHP from January to March 2025. The trimester is part of an ongoing effort to bridge two fiels of Mathematics : the representation theory of locally compact groups and the theory of operator algebras. These research domains share origins in harmonic analysis, spectral theory and quantum mechanics but grew in separate directions. Recent progress in representation theory, involving especially non-Riemannian symmetric spaces and spherical varieties, and new tools developed in operator algebras, especially those involving K-theory and the other methods of non-commutative geometry, offer exciting prospects for new work at the interface between the two fields.

Mini-course are:

• Erik P. van den Ban (Universiteit Utrecht): Harmonic analysis of non-Riemannian symmetric spaces
• Tyrone Crisp (University of Maine): Tempered representations from the point of view of Langlands, and from the point of view of operator algebras
• Omar Mohsen (Université de Paris-Saclay): Introduction to hypoelliptic operators and their index theory
• Hang Wang (East China Normal University): Groups C*-algebras and their K-theory

The purpose of the school is to present a self-contained proof of a famous theorem of Serre in 1972. This theorem tells us that the representation associated to the Galois action on the p-torsion points of an elliptic curve is surjective for p great enough. This theorem had a very great impact in the field of arithmetic geometry and opened the field to numerous problems that are, for some, still open today. After introducing the students to the topics needed to understand the proof, illustrating the theory through exercises and computer sessions, we will present the proof itself.

Intertwining operators are ubiquitous in representation theory. Their construction typically requires a considerable amount of analysis, and they often assume an interesting form. For instance, they are frequently pseudodifferential operators associated with pseudodifferential calculi of intense current study in noncommutative geometry. Conversely, in all multiplicity-one decompositions of representations (e.g. the theta correspondence), the essentially unique intertwining operator, or its symbol, should encode important information on the representation-theoretic decomposition.

However, those operators have received little attention from within operator algebra theory. This meeting will be the occasion to present classical and recent aspects of the theory of intertwining operators and explore the connections between operator algebras and representation theory.

Topics of special interest will include:

• Symmetry breaking operators: special families of intertwining operators between representations of a group and a subgroup. These operators, for Lie groups and algebraic groups over local fields, are the subject of intense study in various settings via analytic, algebraic and geometric methods.
• Concrete study of the intertwining operators appearing in the theta-correspondence over local fields, including interpretations coming from operator algebras and noncommutative geometry.
• Applications of intertwining operators in equivariant index theory and noncommutative geometry, such as K-theoretic constructions based on the BGG complex.

This Thematic Month aims to cover topics related to singularity theory of algebraic or analytic spaces, algebraic study of differential equations, and their applications to questions of transcendence. This 5-week program covers different themes that are often not closely related. One of the main objectives is to make them interact. To encourage participants (especially the youngest ones) to attend the entire month and foster interactions outside each one’s expertise zone, the scientific program of each week of the month will consist of courses accessible to non-experts, as well as more specialized presentations. This month will consist of five successive weeks: – Logarithmic and non-archimedean methods in Singularity Theory. The first week will focus on recent results based on methods in logarithmic geometry and non-archimedean geometry in singularity theory. – Foliations, birational geometry and applications. The second week will cover topics in birational geometry, including singularity resolution, MMP (Minimal Model Program), algebraic foliation theory, and local holomorphic dynamics. – Tame Geometry. The third week will address tame geometry in various forms: o-minimality, transseries, Hardy fields, non-archimedean analogs of tame geometry, and their applications to number theory. – Galois differential Theories and transcendence. The fourth week is devoted to differential Galois theory and its applications to questions of functional transcendence and number theory, as well as the study of periods and E and G-functions. – Enumerative combinatorics and effective aspects of differential equations. The last week is dedicated to enumerative combinatorics and certain effective aspects of differential equations, especially applications in enumerative combinatorics of techniques presented in the previous week, or as effective results on topics covered in the preceding weeks.

The workshop is aimed at algebraic and arithmetic geometers curious about the potential application of model theory in their research, as well as at model theorists who are keen to learn how their tools may be extended to answer questions of geometric interest.

The classification of tempered irreducible representations for real reductive groups was completed in the 1970s by Knapp and Zuckerman, following Harish-Chandra's work on the Plancherel formula. But some aspects of the subject are now undergoing a re-examination, following the discovery of new perspectives. C*-algebras and K-theory are valuable tools in Representation Theory, as shown, for instance, by the Mackey bijection. Indeed, it was the Connes-Kasparov isomorphism in K-theory that motivated the search for a natural bijection between the tempered dual of a real reductive group and the unitary dual of its Cartan motion group, as initially suggested by Mackey in the 1970s.

The meeting will focus on recent developments in which K-theoretic ideas have offered new perspectives on the tempered dual for reductive groups or symmetric spaces, and conversely on new approaches to operator-algebraic problems using contemporary tools in representation theory.

Topics will include:

• New approaches to the Mackey bijection through pseudodifferential operator theory, which has itself undergone an extensive conceptual redesign in the past decade, thanks again to C*-algebra and K-theory connections;
• New perspectives on the the Connes-Kasparov isomorphism using Dirac cohomology and cohomological induction;
• Higher orbital intergrals, which make it possible to go beyond the "noncommutative topology of the tempered dual'', hinting at something like the "differential geometry'' of this noncommutative space;
• Study of the Casselman-Schwartz algebras and their K-theory via Paley-Wiener theorems, and connections with the Connes-Kasparov isomorphism;
• C*-algebraic analysis of the tempered dual from the point of view of G as a symmetric space for GxG, and more generally of the tempered spectrum of symmetric spaces.

K-stability is a central topic in modern complex geometry. It characterises Fano manifolds that admit a Kähler-Einstein metric and provides a good notion of compact moduli space for Fano varieties. The winter school will bring together experts on K-stability who will give 3 mini-courses for PhD students and young researchers with a special focus on explicit problems in dimensions two and three. Along with lecture courses, there will be exercise sessions.

The speakers for the mini-courses are: Hamid Abban (University of Nottingham), Thibaut Delcroix (Université de Montpellier), Elena Denisova (University of Edinburgh), Ruadhaí Dervan (University of Glasgow), Kristin DeVleming (University of San Diego), Erroxe Etxabarri Alberdi (University of Warwick), Kento Fujita (Osaka University), Eveline Legendre (Université de Lyon).

Organising committee: Ivan Cheltsov, Liana Heuberger, Frédéric Mangolte

Scientific committee: Carolina Araujo, Sébastien Boucksom, Simon Donaldson, Chenyang Xu

Speakers:

 Charlotte Chan
 Jessica Fintzen
 Florian Herzig
 Tasho Kaletha 

This is a 4-day workshop that aims to explore connections between p-adic Arthur and ABV packets and geometric representation theory/the geometric Langlands program. It will feature talks from experts in both areas. The primary goal of this workshop is to foster new research directions and collaborations.

Harmonic analysis on homogeneous spaces is a fundamental area of research that simultaneously generalizes classical harmonic analysis on groups and on Riemannian symmetric spaces. It naturally relates to many areas of mathematics, playing a central role in representation theory and the theory of automorphic forms.

This workshop will be an occasion to introduce recent developments in some of these areas. It will also aim to explore new connections between them and extend the fruitful interactions between C*-algebras, harmonic analysis and representation theory beyond the classical setting of groups to the general setting of homogeneous spaces.

Topics will include:

• C*-algebraic approaches to the tempered dual of non-Riemannian symmetric spaces;
• Harmonic analysis and Plancherel theory for spherical spaces;
• Connections with the Langlands program and periods of automorphic forms;
• Recent approaches to the theta correspondence via C*-algebras

The goal of this workshop is to present a panorama of hot topics, and their recent progress, in arithmetic geometry (incl. p-adic Hodge theory, Shimura varieties and their cohomology, L-functions, Berkovich spaces, homotopy and anabelian geometry, Galois theory, condensed mathematics, vanishing cycles, motivic theory, birational geometry,...). Talks will include introductory presentations for graduate students and for PhD researchers.

This is a graduate student workshop on discrete groups in topology and algebraic geometry. This includes topics like fundamental groups of varieties and mapping class groups. This is the second week of a three week long thematic program. The conference the following week may also be of interest to graduate students.

This is a conference on discrete groups in topology and algebraic geometry, which includes topics like fundamental groups of varieties and mapping class groups. This is the third week of a thematic program on the topic.

The 32nd edition of Géométrie Algébrique en Liberté (GAeL) will be hosted by the Institut de Mathématiques de Toulouse from June 16-20, 2025. The deadline for applications is March 2, 2025, and the application form can be found on the website.

The GAeL conferences are a series of annual meetings organised for and by young researchers in algebraic geometry (PhD students and young postdocs). The objective is not only to introduce the participants to subjects that are likely to be of relevance in the forthcoming years, but also to encourage them to actively participate in the mathematical community at an early stage of their career. Each year we invite 3 senior lecturers to give 4 hour mini courses. The rest of the talks are chosen from among the junior participants and are often the first opportunity people get to speak in front of an international audience. We try to keep the atmosphere very friendly and inclusive.

The senior speakers in 2025 will be:

Ada Boralevi (Polytechnic University of Turin)

Talk: Spaces of matrices with rank conditions and more

Tyler Kelly (Queen Mary University of London)

Talk: A guided tour into the mirror

Daniel Loughran (University of Bath)

Talk: Stacks in birational geometry and number theory

In recent years, there has been an explosion of activity surrounding algebraic points on curves, from many different perspectives. These include the study of measures of irrationality, isolated and parametrized points, computational methods to determine algebraic points, and the arithmetic statistics of algebraic points. In this workshop, we aim to bring together researchers from these diverse perspectives, with the particular goal of developing bridges between them. The workshop will include overview talks on the various perspectives, research talks, an open problem session, and structured time for collaboration.

The René 25 conference's purpose is to celebrate the research interests of René Schoof.

During the 2025-26 academic year the School will have a special program on Arithmetic Geometry, Hodge Theory, and O-minimality. Jacob Tsimerman, University of Toronto will be the Distinguished Visiting Professor.

The purpose of this special year will focus on recent developments in hodge theory and o-minimality and their applications to arithmetic geometry. There has been much progress over the last 15 years in using transcendental uniformization maps to study arithmetic questions (general shafarevich theorems, results on unlikely intersections, general bounds on rational point counts). It has become increasingly clear that hodge theory (both classical and P-adic) and the resulting period maps form a natural home for these kinds of investigations to arise. In the other direction, O-minimality has been applied with success to make progress on questions in Hodge theory (Griffiths conjecture, definable period maps), and has recently had its own explosion of results (sharply O-minimal sets, the resolution of Wilkie's conjecture).

The goal of this year will be to bring together researchers in these different fields, with the aim of extending the collaboration between areas, share key insights, and investigate how far existing methods can be pushed.

Senior participants: Gal Binaymini, Ben Bakker (to be confirmed), Jonathan Pila and Claire Voisin (STV)

The Algorithmic Number Theory Symposium (ANTS) is the premier international forum for the presentation of new research in computational number theory and its applications, devoted to algorithmic aspects of number theory and related fields, including elementary number theory, algebraic number theory, analytic number theory, the geometry of numbers, arithmetic geometry, finite fields, cryptography, and coding theory.

On the occasion of 40+ years after the seminar paper of Gross--Zagier, we bring together experts to deliver lectures on a broad range of topics connected with the Gross-Zagier formula, its generalizations, related future directions, and other works that it has inspired.