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## Or choose your own subject tags below

Welcome to MathMeetings.net! This is a list for research mathematics conferences, workshops, summer schools, etc. Anyone at all is welcome to add announcements.

## Know of a meeting not listed here? Add it now!

#### Updates 2019-07

- We're now authenticating email; this should decrease the chance that confirmation emails land in Spam or Junk folders.

Additional update notes are available in the git repository (GitHub).

# Upcoming Meetings

## May 2020

### The Arithmetic of the Langlands Program

Meeting Type: conference

Contact: see conference website

### Description

## June 2020

### On the non-triviality of arithmetic invariants and its applications

Meeting Type:

Contact: see conference website

### Description

### Combinatorial Anabelian Geometry and Related Topics

Meeting Type: conference

Contact: see conference website

### Description

Combinatorial anabelian geometry concerns the reconstruction of scheme- or ring-theoretic objects from more primitive combinatorial constituent data. In this sense, it is closely philosophically related to inter-universal Teichmüller theory.

The purpose of the present workshop is to expose fundamental, introductory aspects of combinatorial anabelian geometry, as well as more recent developments related to the Grothendieck-Teichmüller group and the absolute Galois groups of number fields and mixed-characteristic local fields.

The workshop will also treat results concerning the "resolution of nonsingularities" of hyperbolic curves over mixed-characteristic local fields, such results are closely related to combinatorial anabelian geometry over mixed-characteristic local fields.

### Resolution of singularities, valuation theory and related topics

Meeting Type: conference

Contact: see conference website

### Description

The subject of this meeting covers valuation theory and resolution of singularities, along with some topics that are closely related like the theory of singularities of vector fields, problems concerning arc spaces or the Pierce-Birkhoff Conjecture.

It is our aim to gather together researchers on these transversal subjects in order to strengthen interdisciplinarity between different thematics, to contribute to build a community of researchers working on these problems, to develop new research projects, and to support new collaborations.

### “The Circle Method” Entering its Second Century

Meeting Type: summer school

Contact: see conference website

### Description

The Circle Method emerged one hundred years ago from ideas of Ramanujan, Hardy and Littlewood, and quickly became the most powerful analytic method for counting solutions to Diophantine equations. As the Circle Method enters its second century, new work is making significant advances both in strengthening results in classical Diophantine settings, and in demonstrating applications in novel settings. This includes function field, number field, adelic, geometric, and harmonic analytic applications, with striking consequences in areas such as ergodic theory, subconvexity for L-functions, and the Langlands program.

This summer school for graduate students and postdocs will present accessible lecture series that demonstrate how to apply the Circle Method in a wide variety of settings. Participants will gain both a foundational understanding of the core principles of the Circle Method, and an overview of cutting-edge applications of the method.

Key Speakers: The following speakers will give a lecture series:

```
Timothy Browning (IST Austria)
Jayce Getz (Duke University)
Ritabrata Munshi (Tata Institute)
Simon Myerson (Universität Göttingen)
Lillian Pierce (Duke University)
```

Additional Speakers:

```
Julia Brandes (University of Gothenburg)
Damaris Schindler (University of Utrecht)
Pankaj Vishe (Durham University)
```

### Fourteenth Algorithmic Number Theory Symposium, ANTS-XIV

Meeting Type: conference

Contact: see conference website

### Description

The ANTS meetings, held biannually since 1994, are the premier international forum for the presentation of new research in computational number theory and its applications. They are devoted to algorithmic aspects of number theory, including elementary number theory, algebraic number theory, analytic number theory, geometry of numbers, algebraic geometry, finite fields, and cryptography.

## July 2020

### Motivic, Equivariant and Non-commutative Homotopy Theory

Meeting Type: Summer School

Contact: Aravind Asok, Frédéric Déglise, Grigory Garkusha, Paul Arne Østvær

### Description

The lecture series and research talks at the IHES Summer School will focus on presenting the latest developments in topics related to categories of motives, calculational and foundational aspects of motivic and equivariant homotopy theory, and the generalisations of these tools and techniques in the setting of non-commutative geometry.

### Building Bridges 5th EU/US Summer School and Workshop on Automorphic Forms and Related Topics (BB5)

Meeting Type: Summer School and Workshop

Contact: Samuele Anni, Jim Brown, Jay Jorgenson, Almasa Odžak, Lejla Smajlovic, Lynne Walling

### Description

Automorphic forms are present in almost every area of modern number theory. In recent decades there has been a starburst of activity and progress in this broad area, leading to many new and exciting directions, applications, and connections with other areas. This is a rapidly expanding area, with numerous approaches, tools, and interconnections, as well as connections to other areas of mathematics. The Building Bridges research school offers training to graduate students and early career researchers in the areas of automorphic forms and related topics that continue to be the foci of exciting and influential research activity. The five-day workshop immediately following the summer school aims to foster and strengthen a long-lasting, friendly and supportive exchange between automorphic forms researchers in the EU and the US, and to integrate the summer school students into this community. The organizers have obtained funding to subsidize the costs of successful applicants to the summer school. By popular demand from previous research school and workshop participants, BB5 will take place in Sarajevo, a beautiful city with a friendly, multicultural atmosphere, and low costs of accommodation, food, and transportation.

### Local Langlands and p-adic methods (in honour of Jean-Marc Fontaine)

Meeting Type: conference

Contact: see conference website

### Description

This conference will be on various aspects of the local Langlands correspondence over p-adic fields and methods from p-adic Hodge theory. Topics will include the usual local Langlands correspondence, the p-adic local Langlands correspondence and the relation to coherent sheaves on spaces of Galois representations, and the geometry and cohomology of local Shimura varieties.

### Arithmetic Geometry

Meeting Type: conference

Contact: see conference website

### Description

### ISSAC: International Symposium on Symbolic and Algebraic Computation

Meeting Type: conference

Contact: see conference website

### Description

The International Symposium on Symbolic and Algebraic Computation (ISSAC) is the premier conference for research in symbolic computation and computer algebra. ISSAC 2020 will be the 45th meeting in the series, which started in 1966 and has been held annually since 1981. The conference presents a range of invited speakers, tutorials, poster sessions, software demonstrations and vendor exhibits with a center-piece of contributed research papers.

### Arithmetic statistics and local-global principles

Meeting Type: conference

Contact: see conference website

### Description

The principal aim is to bring together leading researchers interested in the quantitative arithmetic of higher-dimensional varieties on the one hand, and those working on the statistics of algebraic number fields and elliptic curves on the other hand. These two areas have operated more or less independently over the last twenty years, but their borders share an increasingly rich seam of mathematics.

### Higher Dimensional Geometry in New York

Meeting Type: conference

Contact: see conference website

### Description

Higher Dimensional Geometry in NYC is a series of six conferences in Higher Dimensional Geometry which will be held at the Simons Foundation in New York City and at the Simons Centre in Stony Brook over the period 2020-2022.

### Women in Algebraic Geometry

Meeting Type: research collaboration workshop

Contact: see conference website

### Description

The Women in Algebraic Geometry Collaborative Research Workshop will bring together researchers in algebraic geometry to work in groups of 4-6, each led by one or two senior mathematicians. The goals of this workshop are: to advance the frontiers of modern algebraic geometry, including through explicit computations and experimentation, and to strengthen the community of women and non-binary mathematicians working in algebraic geometry. This workshop capitalizes on momentum from a series of recent events for women in algebraic geometry, starting in 2015 with the IAS Program for Women in Mathematics on algebraic geometry.

Successful applicants will be assigned to a group based on their research interests. The groups will work on open-ended projects in diverse areas of current interest, including moduli spaces and combinatorics, degenerations, and birational geometry. Several of the proposed projects extensively involve experimentation and computation, which will increase the likelihood that concrete progress is made over the course of five days and provide useful training in computational mathematics.

### PIMS - Germany Summer School on Eigenvarieties

Meeting Type: summer school

Contact: see conference website

### Description

**Description:**

Non-archimedean geometry is the analogue of complex geometry, where the field of complex numbers is replaced by a field which is complete with respect to a p-adic metric. A fundamental complication is that p-adic spaces are totally disconnected, and therefore basic notions such as analytic con- tinuation must be entirely recast in different language. Nevertheless, the particular properties of the p-adic topologies, while perverse in some sense, provide the key to a rich, fulfilling, and ultimately productive theory. There are various manifestations of non-archimedean geometry, e.g. rigid analytic spaces a la Tate, Berkovich spaces or adic spaces a la Huber. For this summer school we take the point of view of adic spaces with emphasis on rigid analytic spaces which form special examples. Indeed, non-archimedean geometry and the associated area of p-adic Hodge theory for Galois representations play a central role in modern algebraic number theory. It has become increasingly clear that active researchers in algebraic number theory would be greatly benefitted by having a working knowledge of p-adic geometric methods.

Eigencurves - and more generally, eigenvarieties - are rigid analytic versions of modular curves, which parametrize p-adic families of modular forms. The study of such families may be said to have started with Serre in the 1970s, and was extensively developed by Hida in the 1980s; Hida's work on the so-called ordinary modular forms, in particular, was deeply influential in the eventual proof of modularity of elliptic curves by Wiles and others in 1994. However, it was clear even from looking at Serre's results, that a fully satisfactory theory of p-adic families would require consideration of non-ordinary forms, and that such a theory would necessarily require fundamental new ideas. These results were eventually supplied by Coleman in the mid-1990s, and the eigencurve parametrizing was introduced as a parameter space by Coleman and Mazur shortly thereafter. The subject has exploded in the last decades, with generalizations of the eigencurve to higher rank groups, and with the use of increasingly sophisticated technology from p-adic geometry. Furthermore, p-adic families of automorphic forms have taken on an increasingly important role in modern number theory.

The subject of eigencurves lies somewhere between classical arithmetic geometry represented in Canada, and p-adic geometry which is well-represented in Germany, and this we propose to take advantage of the complementary expertise and the broad outlines of a PIMS/Germany collaboration to organize an event where both sides can benefit. Thus, the proposed workshop on eigenvarieties will be an instructional school for students, postdocs, and researchers in other fields. The goal is to provide beginners with a working knowledge of this immensely active and important field, and to encourage collaborations between German researchers and those at PIMS Institutes around the general workshop themes.

**Topics of Instruction:**

The goal of the course will be to understand the foundational work of Coleman, and Coleman-Mazur, and eventually to study the paper on the generalization to the higher dimensional case given by Buzzard. A good overview of the subject is given in the survey article of Kassei.

**Invited Speakers:**

- John Bergdall, Bryn Mawr College, USA
- George Boxer, University of Chicago, USA
- David Hansen, Max Planck Institute, Germany
- Eugen Hellman, University of Münster
- Christian Johansson, Chalmers Institute of Technology, Sweden
- Judith Ludwig, University of Heidelberg, Germany
- James Newton, King’s College, England
- Vincent Pilloni, Ecole Normale Supérieure de Lyon, France

## August 2020

### Stacks Project Workshop 2020

Meeting Type: workshop (appropriate for graduate students)

Contact: Pieter Belmans, Aise Johan de Jong, Wei Ho

### Description

This will be a workshop in arithmetic and algebraic geometry, similar to the previous iteration (https://stacks.github.io/2017/). The intended participant is a graduate student, or a postdoc, or even a senior researcher. You will work on a single topic in a small group together with a mentor for a week with the aim of producing a text that will be considered for inclusion in the Stacks Project. Part of this process will be seeing how one builds new theory from the foundations. There will also be one or two talks per day covering advanced topics in arithmetic or algebraic geometry.

The Stacks project workshop will have some optional activities you won't see at other workshops. Adding references to and finding mistakes in the Stacks Project (and fixing them) as well as activities related to LaTeX use, Git, and GitHub. Overall these will be aimed at helping you contribute efficiently to the Stacks Project.

### The Eighth Pacific Rim Conference in Mathematics

Meeting Type: Conference

Contact: Alan Hammond and Fraydoun Rezakhanlou

### Description

The Eighth Pacific Rim Conference on Mathematics will be held at the University of California at Berkeley from Monday 3th August to Friday 7th August 2020. The PRCM will be a high profile mathematical event that will cover a wide range of exciting research in contemporary mathematics. Its objectives are to offer a venue for the presentation to and discussion among a wide audience of the latest trends in mathematical research, and to strength ties between mathematicians working in the Pacific Rim region. The conference will provide junior researchers with opportunities to engage and collaborate with established colleagues within and between the many represented mathematical disciplines.

### School on Hodge Theory and Shimura Varieties

Meeting Type: summer school

Contact: Ulrich Görtz

### Description

Mini-courses by Matt Kerr, Andreas Mihatsch, Colleen Robles, plus a couple of research talks.

### Global Langlands, Shimura varieties, and shtukas

Meeting Type: conference

Contact: see conference website

### Description

This conference will be on various aspects of the global Langlands correspondence. Topics will include in particular the geometry and cohomology of Shimura varieties and more general locally symmetric spaces, or moduli spaces of shtukas.

### Decidability, definability and computability in number theory

Meeting Type: research program

Contact: see conference website

### Description

This program is focused on the two-way interaction of logical ideas and techniques, such as definability from model theory and decidability from computability theory, with fundamental problems in number theory. These include analogues of Hilbert's tenth problem, isolating properties of fields of algebraic numbers which relate to undecidability, decision problems around linear recurrence and algebraic differential equations, the relation of transcendence results and conjectures to decidability and decision problems, and some problems in anabelian geometry and field arithmetic. We are interested in this specific interface across a range of problems and so intend to build a semester which is both more topically focused and more mathematically broad than a typical MSRI program.

### Connections for Women: Decidability, definability and computability in number theory

Meeting Type: conference

Contact: see conference website

### Description

The aim of the workshop is to discover how the problems in number theory and algebraic geometry arising from the Hilbertâ€™s tenth problem for rationals interact with the ideas and techniques in mathematical logic, such as definability from model theory and decidability and degree-theoretic complexity from computability theory. This interaction includes various analogues of Hilbertâ€™s tenth problem and related questions, focusing on the connections of algebraic, number-theoretic, model-theoretic, and computability-theoretic properties of structures and objects in algebraic number theory, anabelian geometry, field arithmetic, and differential algebra.

### Low-Dimensional Topology and Number Theory

Meeting Type: conference

Contact: see conference website

### Description

### Introductory Workshop: Decidability, definability and computability in number theory

Meeting Type: conference

Contact: see conference website

### Description

Our workshop will focus research efforts on the interaction of number-theoretic questions with questions of decidability, definability, and computability, bringing together researchers approaching these questions from various sides to work on the core issues. This Introductory Workshop will serve as the introductory event of the MSRI semester program and is designed to introduce the basic structures and ideas of the different communities, and to highlight problems of active current interest.

### Modern Breakthroughs in Diophantine Problems

Meeting Type: conference

Contact: see conference website

### Description

### Automorphic Forms and Arithmetic

Meeting Type: conference

Contact: see conference website

### Description

### Serre weights conjectures and geometry of Shimura varieties

Meeting Type: conference

Contact: see conference website

### Description

This conference is dedicated to studying recent advancements concerning Serre weights conjectures and the geometry of Shimura varieties and, in particular, the interaction between these two areas.

### Number Theory-Cohomology in Arithmetic

Meeting Type: thematic research program

Contact: see conference website

### Description

Homological tools and ideas are pervasive in number theory. To defend this assertion, it suffices to evoke the role of étale cohomology in the study of the zeta functions of varieties over finite fields through the Weil conjectures, or the cohomological approach to class field theory formulated by Artin and Tate in the 1950's. The theory of motives, a manifestation of a universal cohomology theory attached to algebraic varieties, and the attendant motivic cohomology plays a central role in describing the special values of L-functions of varieties over number fields, via the conjectures of Deligne, Beilinson-Bloch, and Bloch-Kato. Much progress in the Langlands program exploits the fruitful connection between automorphic representations and the cohomology of associated Shimura varieties and more general arithmetic quotients of locally symmetric spaces. The study of special values of L-functions and the Langlands program, widely perceived as two fundamental yet seperate strands of the subject in the early 1990's, were beautifully unified in Wiles' epoch-making proof of the Shimura-Taniyama conjecture, in which this conjecture was reduced to a special instance of the Bloch-Kato conjecture for the symmetric square motive of an elliptic curve. Recent years have seen great strides in our understanding of the cohomology of the arithmetic quotients arising in the study of automorphic representations, spurred in part by the desire to extend the range of applicability of the celebrated Taylor-Wiles method. This has led to new automorphy and potential automorphy results: most spectacularly, perhaps, for abelian surfaces, as well as elliptic curves over general CM fields.

## September 2020

### Arithmetic Aspects of Algebraic Groups

Meeting Type: conference

Contact: see conference website

### Description

The Banff International Research Station will host the "Arithmetic Aspects of Algebraic Groups" workshop in Banff from September 6 to September 11, 2020.

The investigation of arithmetic groups has been an active and important area of mathematical research ever since it arose in the work of Gauss, Klein, Poincare, and other famous mathematicians of the 18th and 19th centuries. New points of view have recently led to progress on classical problems, opened new directions of inquiry, and revealed unexpected connections with other areas of mathematics. The workshop will bring together experts in the area, researchers in related fields, and young mathematicians who wish to learn about the most recent advances and the most promising directions for the future of the field.

### Arakelov Geometry

Meeting Type: conference

Contact: Prof. Dr. Klaus Künnemann

### Description

The conference **Arakelov Geometry** is organized by

**José Ignacio Burgos Gil, Walter Gubler, and Klaus Künnemann**.

This conference constitutes the eleventh session of the Intercity Seminar on Arakelov Theory organized by Jose Ignacio Burgos Gil, Vincent Maillot and Atsushi Moriwaki with previous sessions in Barcelona, Beijing, Copenhagen, Kyoto, Paris, Regensburg, and Rome.

### Analytic and Geometric Number Theory

Meeting Type: Conference

Contact: Daniel Loughran

### Description

This conference is part of the celebration of the recent creation of the new Number Theory group at the University of Bath.

It will revolve around topics in analytic number theory, algebraic number theory, and algebraic geometry, related to the study of Diophantine equations.

Speakers:

```
Tim Browning (IST, Vienna)
Jean-Louis Colliot-Thélène (Orsay)
Ulrich Derenthal (Hannover)
Christopher Frei (Manchester)
Rachel Newton (University of Reading)
Alexei Skorobogatov (Imperial College London)
Arne Smeets (Nijmegen)
Efthymios Sofos (Glasgow)
```

### Arizona Winter School Undergraduate Bootcamp

Meeting Type: undergraduate school

Contact: see conference website

### Description

In cooperation with the Arizona Winter School (http://swc.math.arizona.edu), Pomona College will host the AWS Undergraduate Bootcamp. This 2-day intensive program, targeted for underrepresented minority students, will showcase number theory at the introductory level. This will take place on Saturday, September 12 and Sunday, September 13 in Millikan Laboratory at Pomona College in Claremont, California. All events are free.

There will be four types of events:

```
Expository Talks
Experts in number theory will give one-hour presentations on various topics.
Tutorial
A faculty member will give three lectures over two days on "Automorphic Forms." (The Arizona Winter School 2021 will be on "Modular forms beyond GL(2)".)
Problem Sessions
Two graduate students will coordinate a series of one-hour sessions where students will work in groups on problems meant to supplement the tutorials.
Panel Discussions
There will be two panels on topics to be announced.
```

### Non-Archimedean and tropical geometry

Meeting Type: Workshop

Contact: see conference website

### Description

### p-adic L-functions and Euler systems in honor of Bernadette Perrin-Riou

Meeting Type: conference

Contact: see conference website

### Description

In Iwasawa Theory, one of the central questions is the study of the Iwasawa main conjecture, which relates the characteristic ideal of the Selmer group of a motive to its p-adic L-function (when it exists). This in turn leads to information on the Bloch-Kato conjecture, a generalization of the Birch and Swinnerton-Dyer conjecture. Cases of the Iwasawa main conjecture have been established using the machinery of Euler systems, which are collections of cohomology classes satisfying certain norm relations and are related to the L-function of a motive and were first introduced and exploited in the late 80s and early 90s in the works of Thaine, Kolyvagin, Rubin, and Kato.

Bernadette Perrin-Riou, one of the influential, pioneering figures in Iwasawa Theory in the 1990s, is widely acclaimed for the influential ideas she has brought to the subject. Her deep study of the Euler system originally constructed by Kato led to the introduction of her fundamental `big logarithm map" (often refereed as the`

Perrin-Riou map" nowadays), which is a far reaching generalisation of the Coleman power series and is one of the key ingredients in establishing links between Euler systems and p-adic L-functions. Her work also initiated the study of higher rank Euler systems and has been a source of inspiration for many further developments in this direction. Likewise, her p-adic analogue of the Gross-Zagier formula has opened up an area of enquiry that remains active and fertile to the present day. All these, as well as many other important contributions of Perrin-Riou, continue to serve as a model and a guide for today's research in Iwasawa Theory. This workshop is therefore dedicated to the celebration of her 65th birthday.

In the first decade of this century, further progress in the theory of Euler systems was stymied by the fact that few instances were known beyond the basic examples (circular units, elliptic units, Heegner points, and Beilinson elements) introduced and exploited by Thaine, Rubin, Kolyvagin and Kato respectively. Around 2010, the scope of Kato's construction was extended to encompass p-adic families of cohomology classes arising from Beilinson-Flach elements, and diagonal cycles in triple products of Kuga-Sato varieties, with application to the Birch and Swinnerton conjecture in analytic rank zero, in the spirit of the early work of Coates and Wiles. Important progress was then made in establishing the Euler system norm compatibilities of Beilinson-Flach elements. This has opened the floodgates for a wide variety of new Euler system constructions, applying notably to the Rankin-Selberg convolution of two modular forms, Siegel modular forms on GSp(4) and GSp(6), as well as Hilbert modular surfaces. At around the same time, and quite independently, a markedly different strategy has been proposed for studying diagonal on triple products based on congruences between modular forms instead of $p$-adic deformations, leading to remarkable constructions whose scope has the potential to surpass the more traditional approach based on norm-compatible elements. Finally, important progress arising from the method of Eisenstein congruences offer a powerful complementary approach, greatly contributing to the power, usefulness, and widening appeal of Euler system techniques.

The workshop will precede the annual Quebec-Maine conference which will take place at Laval University on Saturday and Sunday (September 26-27, 2020). The workshop will end on Friday at noon so that those who wish to attend can travel to Quebec City in the afternoon. (A roughly 3 hour trip by train or by bus.)

### Witt vectors in Algebra and Geometry

Meeting Type: conference

Contact: see conference website

### Description

Witt vectors are well-known for their ability to pop up in unexpected places, and can serve as a good starting point for a conversation on many interesting and diverse mathematical subjects. The goal of the conference is to have such a conversation on several recent subjects where Witt vectors appeared yet again (including but not limited to the usual and topological Hochschild Homology, both commutative and non-commutative, prismatic cohomology and p-adic Hodge theory, polynomial functors, geometric representation theory in char p).

## October 2020

### Arithmetic quotients of locally symmetric spaces and their cohomology

Meeting Type: conference

Contact: see conference website

### Description

If G is a reductive algebraic group over Z, the group G(Z) of its integral points (or any congruence subgroup thereof) acts discretely on the locally symmetric space X:= G(R)/K, where K is a maximal compact subgroup of G(R). The quotients G(Z) X play a fundamental role in the theory of automorphic forms and in number theory. Notably, their cohomology is a rich source of invariants attached to automorphic representations of G, and thus plays a central role in the Langlands program. A fundamental trichotomy governing the topological behaviour of such arithmetic quotients was proposed around 2010 by Bergeron and Venkatesh. A single positive integer d, depending only on the overlying symmetric space X, dictates the expected behaviour of the homology of the arithmetic quotient. When d=0, the cohomology is expect to have very little torsion but lots of characteristic 0 homology, which can be studied via analytic and transcendental methods (de Rham cohomology, Hodge theory). Shimura varieties and even-dimensional real hyperbolic spaces fall into this class. When d=1, one expects to find a lot of torsion but very little characteristic 0 homology. Odd dimensional hyperbolic manifolds, such as the Bianchi three-fold SL2(Z[i]) SL2(C)/U(2), fall into this case. When d is greater than 1, one expects little torsion and little characteristic zero homology.

There has been remarkable progress towards understanding how this trichotomy interacts with arithmetic: When d = 0, several interesting recent torsion-freeness results have been obtained by researchers like Caraiani, Emerton, Gee, and Scholze. When d=1, one can ask whether torsion always arises when it's expected to, and with the expected abundance. Torsion can be probed analytically using the Cheeger-Muller theorem. But there are obstructions ("tiny eigenvalues" and "very complex cycles"), which are very interesting in their own right, and need to be overcome in order to prove that there's as much torsion as expected. This torsion growth problem, especially for hyperbolic three-manifolds, has a life of its own even outside number theory, notably in the community of geometric groups theorists. Among the most striking developments arising in the relatively less well explored setting where d is larger than 1, let us mention Peter Scholze's construction of Galois representations attached to (possibly torsion) eigenclasses in the cohomology of arithmetic quotients, which is especially deep in this case. Another highly promising, fundamental breakthrough is manifested in Akshay Venkatesh's conjecture on derived Hecke algebras, which is expected to play an important role in extending the scope of the Taylor-Wiles method beyond the setting of d=0 to which it had been confined until relatively recently. The deep study of torsion in homology and analytic torsion carried out earlier by Bergeron, Venkatesh and others played a very important part in the nascent theory of derived Hecke operators and the attendant motivic action on the cohomology of arithmetic groups. In some very special instances, where G=GL(2) and one focusses on the coherent cohomology of an arithmetic quotient with values in certain automorphic sheaves, Venkatesh's conjectures exhibit a tantalising connection with certain ``tame refinements", in the spirit of conjectures of Mazur and Tate, of conjectures on the values of triple product p-adic L-functions.

The field is still in a very exploratory stage in which precise expectations (conjectural or otherwise) have not yet fully cristallised. For instance, there does not yet seem to be a reasonable conjecture about "how much cohomology", torsion or characteristic zero, to expect when d is greater than 1. Among other reasons, this makes computing in this setting very interesting. The workshop is expected to have a significant computational and experimental component, in which various experts will report on experimental data that might prove valuable in solidifying our expectations.

## November 2020

### WIN5: Women in Numbers 5

Meeting Type: conference

Contact: see conference website

### Description

The Banff International Research Station will host the "WIN5: Women in Numbers 5" workshop in Banff from November 15 to November 20, 2020.

Despite recent progress in gender equality in STEM fields, women continue to be underrepresented in the research landscape of many areas of mathematics, including number theory. The Women in Numbers (WIN) network was created in 2008 for the purpose of increasing the number of active female researchers in number theory. For this purpose, WIN sponsors regular conferences, taking place approximately every three years, where female scholars gather to collaborate on cutting-edge research in the field and produce publishable scientific results. The WIN workshops provide an ongoing forum for involving each new generation of junior faculty and graduate students in state-of-the-art research in number theory. They have to come be highly regarded among the broader number theory community due to the quality of research produced by these collaborations.

WIN5 is the fifth in this series of events, bringing together female number theorists at various career stages for research collaboration and mentorship. As always, the scientific program will centre on onsite collaboration on open research problems in number theory, conducted in small groups comprised of senior and junior scholars as well as graduate students. Groups will publish their initial finding in a peer-reviewed conference proceedings volume, and research partnerships formed at the WIN5 workshop are expected to last well beyond the duration of the event. WIN projects have the potential to grow into fruitful long-term research alliances that have a transforming influence on participants' careers and a significant positive impact on the research landscape in number theory. Past WIN workshop project groups have matured into highly effective research teams producing ongoing scholarly work of exceptional scientific quality.

### Langlands Program: Number Theory and Representation Theory

Meeting Type: conference

Contact: see conference website

### Description

The Casa MatemÃ¡tica Oaxaca (CMO) will host the "Langlands Program: Number Theory and Representation Theory" workshop in Oaxaca, from November 29 to December 04, 2020.

Langlands functoriality conjectures predict a vast generalization of the classical reciprocity laws of Class Field Theory, providing crossroads between Number Theory and Representation Theory. The conjectures are both local and global and pertain a connected reductive group and its Langlands dual group.

We aim to introduce young mathematicians in M\'exico and Latin-America to topics of current research in the Langlands Program. We will also promote the participation women and of graduate students from a diverse background in a workshop where experts in the field from across the world will gather to expand upon the frontiers of current research. In addition to research talks, there will be three courses that will also be accessible to mathematicians working in closely related fields.

## December 2020

### p-adic cohomology, p-adic families of modular forms, and p-adic L-functions

Meeting Type: conference

Contact: see conference website

### Description

The workshop will be devoted to the varied and fruitful interactions between p-adic cohomology theories, the theory of p-adic deformations of modular forms and Galois representations, and the construction of p-adic L-functions arising from the latter using techniques drawn from the former, with special emphasis on their rich array of arithmetic applications.

The field of p-adic automorphic forms has seen a huge development in the last decades with the construction of p-adic families in many new context. Among this one can cite Hansen's construction of eigenvarieties using overconvergent cohomology, and the coherent approach using (partial) Igusa towers of Andreattaâ€“Iovitaâ€“Pilloni. There have been immediate applications to the construction of p-adic L-functions in families and to the proof of several instances of the conjectures by Greenberg and Benois on trivial zeroes, such as the work of Barreraâ€“Dimitrovâ€“Jorza.

But the existence of these eigenvarieties have proved to be useful also for the study of many other interesting arithmetic problems.

The first example is given by the applications to the Blochâ€“Kato conjecture. Bloch and Kato conjectured that the most interesting arithmetic information concerning varieties (and more generally, geometric Galois representations) are contained in two objects: the Selmer group and the L-function. They also conjecture that all the information coming from the Selmer group can be recovered from the L-function. Some special cases of this conjecture have been proven: we cite for example the work of Bellaicheâ€“Chenevier for unitary groups and Skinnerâ€“Urban for elliptic curves in rank less or equal than 2. The key ingredients in these works is the use of deformations of automorphic forms and their Galois representations in p-adic families to construction elements in the Selmer group.

Another example is the study of local properties of Galois representations and the corresponding p-adic Hodge theory. We cite the work of Kedlaya, Pottharst, and Xiao concerning the existence of triangulations in families for p-adic representations of p-adic fields arising from finite slope automorphic forms. Other related results are the works on the smoothness of eigenvarieties at critical points by Bergdall and Breuilâ€“Hellmannâ€“Schraen; it has implication on the existence of companion forms, which are different p-adic automorphic forms sharing the same Galois representations (such as a CM form and its Serre antiderivative).

Very recently two new geometric approaches have been developed in the study of p-adic families and their L-functions.

Andreatta and Iovita introduced the idea of vector bundles with marked sections, which not only allows one to recover their previous constructions of eigenvarieties but let them p-adic interpolate in families the de Rham cohomology of the modular curve and the Gaussâ€“Manin connection. They can then construct triple product p-adic L-functions for finite slope families and anticyclotomic p-adic L-functions when p is inert in the CM field.

At the same time, the introduction of perfectoid spaces and adic geometric has brought new and fresh ideas in the field: one can cite the new construction of classical eigenvarieties by Chojeckiâ€“Hansenâ€“Johansson using functions on the perfectoid tower of modular curves and the construction by Kriz of a new p-adic Maassâ€“Shimura operator and anticyclotomic p-adic L-functions in the inert case. His strategy relies on Scholze's Hodge to de Rham comparison isomorphism, which has been recently upgraded to an integral comparison map by Bhattâ€“Morrowâ€“Scholze.

These new geometric tools have already allowed the construction of new p-adic L-functions; the aim of the workshop is to bring together arithmetic people with the experts in these two innovative approaches to find new exciting applications, both to global (Galois representations and their L-functions) and local (integral p-adic Hodge theory) problems.

## January 2021

### Moduli spaces and Modular forms

Meeting Type: invitational workshop

Contact: see conference website

### Description

## February 2021

### Combinatorial Algebraic Geometry

Meeting Type: thematic research program

Contact: see conference website

### Description

Combinatorial algebraic geometry comprises the parts of algebraic geometry where basic geometric phenomena can be described with combinatorial data, and where combinatorial methods are essential for further progress.

Research in combinatorial algebraic geometry utilizes combinatorial techniques to answer questions about geometry. Typical examples include predictions about singularities, construction of degenerations, and computation of geometric invariants such as Gromov-Witten invariants, Euler characteristics, the number of points in intersections, multiplicities, genera, and many more. The study of positivity properties of geometric invariants is one of the driving forces behind the interplay between geometry and combinatorics. Flag manifolds and Schubert calculus are particularly rich sources of invariants with positivity properties.

In the opposite direction, geometric methods provide powerful tools for studying combinatorial objects. For example, many deep properties of polytopes are consequences of geometric theorems applied to associated toric varieties. In other cases geometry is a source of inspiration. For instance, long-standing conjectures about matroids have recently been resolved by proving that associated algebraic structures behave as if they are cohomology rings of smooth algebraic varieties.

Much research in combinatorial algebraic geometry relies on mathematical software to explore and enumerate combinatorial structures and compute geometric invariants. Writing the required programs is a considerable part of many research projects. The development of new mathematics software is therefore prioritized in the program.

The program will bring together experts in both pure and applied parts of mathematics as well mathematical programmers, all working at the confluence of discrete mathematics and algebraic geometry, with the aim of creating an environment conducive to interdisciplinary collaboration. The semester will include four week-long workshops, briefly described as follows.

A 'boot-camp' aimed at introducing graduate students and early-career researchers to the main directions of research in the program.

A research workshop dedicated to geometry arising from flag manifolds, classical and quantum Schubert calculus, combinatorial Hodge theory, and geometric representation theory.

A research workshop dedicated to polyhedral spaces and tropical geometry, toric varieties, Newton-Okounkov bodies, cluster algebras and varieties, and moduli spaces and their tropicalizations.

A Sage/Oscar Days workshop dedicated to development of programs and software libraries useful for research in combinatorial algebraic geometry. This workshop will also feature a series of lectures by experts in polynomial computations.

## May 2021

### Harmonic Analysis and Analytic Number Theory

Meeting Type: conference

Contact: see conference website

### Description

### Leuca2021 Celebrating Claude Levesque's and Michel Waldschmidt's 75th birthdays

Meeting Type: conference

Contact: Valerio Talamanca

### Description

### QUANTUM CHAOS AND NUMBER THEORY A conference in honor of Zeev Rudnick's 60 birthday

Meeting Type: conference

Contact: Lior Rosenzweig

### Description

The conference “Analytic Number Theory, Quantum Chaos and their Interfaces” aims at gathering distinguished researchers working in either of the disciplines to discuss recent research advances in these fields, and serve as a playground for the exchange of ideas between these, rather diverse, research communities. Another purpose of our conference is to provide a solid educational platform for more junior researchers (PhD students, postdoctoral researchers and early career permanent faculty) who aspire to conduct research in the relevant fields and expose them to some of the outstanding results and open problems as well as to meet other researchers with similar academic interests, with high potential to start new research collaborations. Being a home to Professor Zeev Rudnick, who has contributed greatly to unifying the main subjects of the conference and established some relevant fundamental results in these fields, Tel Aviv University is a natural place for such a meeting to take place.

## July 2021

### Fundamental Groups and their Representations in Arithmetic Geometry

Meeting Type: conference

Contact: see conference website

### Description

In arithmetic geometry, one studies solutions to polynomial equations defined with arithmetically interesting coefficients, such as integers or rational numbers. One way to study such objects, which has seen tremendous success in the last several decades, is by investigating their symmetries. Quite surprisingly, in several interesting situations, many of the geometric and arithmetic properties of the objects in question are actually controlled by the object’s symmetries.

Unfortunately, it is usually impossible to study these symmetries directly with current technology. To get around this, mathematicians working in this area often study simplified (often linearized) versions of the symmetries in question, which still capture a significant amount of information about the given object. This workshop will bring together both senior and junior researchers, including graduate students, postdocs, and leading experts, who study objects of geometric and arithmetic origin from the point of view of their symmetries and their linearized variants.

### Geometry via Arithmetic

Meeting Type: conference

Contact: see conference website

### Description

There is an age-old relationship between arithmetic and geometry, going back at least to Euclid's Elements. Historically, it has usually been geometry that has been used to enrich our understanding of arithmetic, but the purpose of this workshop is to study the flow of information in the other direction. Namely, how can arithmetic enhance our understanding of geometry? This meeting will bring together researchers from both sides of the partnership, to explore ways to bind the two fields ever closer together.

### Arithmetic Aspects of Deformation Theory

Meeting Type: conference

Contact: see conference website

### Description

One focus of modern number theory is to study symmetries of numbers that are roots of polynomial equations. Collections of such symmetries are called Galois groups, and they often encode interesting arithmetical information. The theory of Galois representations provides a way to understand these Galois groups and in particular, how they interact with other areas of mathematics. This workshop will investigate how these Galois representations can be put together into families, and search for new arithmetic applications of these families.

### Explicit Methods in Number Theory

Meeting Type: workshop

Contact: Karim Belabas, Bjorn Poonen, Fernando Villegas

### Description

The workshop will bring together people attacking key problems in number theory via techniques involving concrete or computable descriptions. Here, number theory is interpreted broadly, including algebraic and analytic number theory, Galois theory and inverse Galois problems, arithmetic of curves and higher-dimensional varieties, zeta and *L*-functions and their special values, and modular forms and functions. Considerable attention is paid to computational issues, but the emphasis is on aspects that are of interest to the pure mathematician.

### A Pair of Automorphic Workshops 2021

Meeting Type: graduate instructional workshop (week 1) and collaborative research workshop (week 2)

Contact: Ellen Eischen

### Description

During the last two weeks of July 2021, the University of Oregon will host a graduate instructional workshop followed by a collaborative research workshop to promote diverse collaborations.

While both of these workshops focus on algebraic and p-adic aspects of automorphic forms, L-functions, and related topics, the two workshops are independent. Applicants are encouraged to apply for one or both of the workshops, and funding decisions will be determined separately for each.

### Rational Points 2021

Meeting Type: workshop

Contact: Michael Stoll

### Description

This workshop aims at bringing together the leading
experts in the field, covering a broad spectrum reaching from the more theoretically-oriented over
the explicit to the algorithmic aspects. The fundamental problem motivating the workshop
asks for a description of the set of rational points *X*(**Q**) for a given
algebraic variety *X* defined over **Q**. When *X* is a curve,
the structure of this set is known, and the most interesting question is
how to determine it explicitly for a given curve. When *X* is higher-dimensional,
much less is known about the structure of *X*(**Q**), even when *X*
is a surface. So here the open questions are much more basic for our
understanding of the situation, and on the algorithmic side, the focus is
on trying to decide if a given variety does have any rational point at all.

This is a workshop with about 50 participants.
Participation is **by invitation**. Every participant
is expected to contribute actively to the success of the event, by
giving talks and/or by taking part in the discussions.

## August 2021

### Diophantine Methods in Algebraic Dynamics

Meeting Type: conference

Contact: see conference website

### Description

Algebraic dynamics is the study of discrete dynamical systems on algebraic varieties. It has its origins in complex dynamics, where one studies self-maps of complex varieties, and now encompasses dynamical systems defined over global fields.

In recent years, researchers have fruitfully investigated the latter by applying number-theoretic techniques, particularly those of Diophantine approximation and geometry, subfields which study the metric and geometric behavior of rational or algebraic points of a variety. The depth of this connection has allowed the mathematical arrow between the two fields to point in both directions; in particular, arithmetic dynamics is providing new approaches to deep classical Diophantine questions involving the arithmetic of abelian varieties. This workshop will focus on communicating and expanding upon the connections between algebraic dynamics and Diophantine geometry. It will bring together leading researchers in both fields, with an aim toward synthesizing recent advances and exploring future directions and applications.

### Géométrie algébrique, Théorie des nombres et Applications (GTA)

Meeting Type: conference

Contact: Gaetan Bisson

### Description

The GTA 2021 conference will bring together world class researchers in mathematics. Its main objectives are to discuss recent advances in the fields of algebraic geometry, number theory and their applications, as well as to foster international collaborations on connected topics.

Although contributions from all related areas of mathematics are welcome, particular emphasis will be placed on research interests of our late colleague Alexey Zykin, namely: zeta-functions and L-functions, algebraic geometry over finite fields, families of fields and varieties, abelian varieties and elliptic curves.

### Supersingular Isogeny Graphs in Cryptography

Meeting Type: conference

Contact: see conference website

### Description

Despite the enormous commercial potential that quantum computing presents, the existence of large-scale quantum computers also has the potential to destroy current security infrastructures. Post-quantum cryptography aims to develop new security protocols that will remain secure even after powerful quantum computers are built. This workshop focuses on isogeny-based cryptography, one of the most promising areas in post-quantum cryptography. In particular, we will examine the security, feasibility and development of new protocols in isogeny-based cryptography, as well as the intricate and beautiful pure mathematics of the related isogeny graphs and elliptic curve endomorphism rings. To address the goals of both training and research, the program will be comprised of keynote speakers and working group sessions.

### Automorphic Forms, Geometry and Arithmetic

Meeting Type: invitational workshop

Contact: see conference website

### Description

## September 2021

### Arithmetic Geometry - Takeshi 60

Meeting Type: conference

Contact: Ahmed Abbes, Kenichi Bannai, Naoki Imai, Tadashi Ochiai, Atsushi Shiho

### Description

A conference on the occasion of Takeshi Saito's 60th birthday

### 2nd IMA Conference on Mathematics of Robotics

Meeting Type: conference

Contact: Pam Bye

### Description

This Conference has been organised in cooperation with the Society for Industrial and Applied Mathematics (SIAM).

Areas of interest include, but are not limited to: Topology. Kinematics. Algebraic topology of con?guration spaces of robot mechanisms. Topological aspects of path planning and sensor networks. Differential topology and singularity theory of robot mechanism and moduli spaces. Algebraic Geometry. Varieties generated by linkages and constraints. Geometry of stiffness and inertia matrices. Rigid-body motions. Computational approaches to algebraic geometry. Dynamical Systems and Control. Dynamics of robots and mechanisms. Simulation of multi-body systems, e.g. swarm robots. Geometric control of robots. Optimal control and other optimisation problems. Combinatorial and Stochastic Methods. Rigidity of structures. Path planning algorithms. Modular robots. Statistics. Stochastic control. Localisation. Navigation with uncertainty. Statistical learning theory. Cognitive Robotics. Mathematical aspects of Artificial Intelligence, Developmental Robotics and other Neuroscience based approaches.

Invited speakers: Dr Mini Saag – University of Surrey, UK Prof Frank Sottile - Texas A&M University, USA Prof Stefano Stramigioli - University of Twente, The Netherlands

## October 2021

### Lattices and Cohomology of Arithmetic Groups: Geometric and Computational Viewpoints

Meeting Type: conference

Contact: see conference website

### Description

A lattice is a discrete collection of regularly ordered points in space. Lattices are everywhere around us, from the patterned stacked arrangements of fruits and vegetables at the grocery to the regular networks of atoms in crystalline compounds. Today lattices find applications throughout mathematics and the sciences, applications ranging from chemistry to cryptography and Wi-Fi networks.

The focus of this meeting is the connections between lattices and number theory and geometry. Number theory, one of the oldest branches of pure mathematics, is devoted to the study properties of the integers and more sophisticated number systems. Lattices and number theory have many deep connections. For instance using number theory it was recently demonstrated that certain packings of balls in high dimensions are optimally efficient. Lattices also appear naturally when one studies certain spaces that play an important role in number theory; one of the main focuses of this meeting is to investigate computational and theoretical methods to understand such spaces and to expand the frontier of our algorithmic knowledge in working with them.

### Cohomology of Arithmetic Groups: Duality, Stability, and Computations

Meeting Type: conference

Contact: see conference website

### Description

The cohomology of arithmetic groups is the study of the properties of ``holes'' in geometric spaces that contain information about number theory. The workshop will bring together mathematicians with expertise in number theory, topology, and geometric group theory to tackle these problems and explore recent developments.

## June 2022

### 7th IMA Conference on Numerical Linear Algebra and Optimization

Meeting Type: conference

Contact: Pam Bye

### Description

The success of modern codes for large-scale optimization is heavily dependent on the use of effective tools of numerical linear algebra. On the other hand, many problems in numerical linear algebra lead to linear, nonlinear or semidefinite optimization problems. The purpose of the conference is to bring together researchers from both communities and to find and communicate points and topics of common interest. This Conference has been organised in cooperation with the Society for Industrial and Applied Mathematics (SIAM). Conference topics include any subject that could be of interest to both communities, such as: • Direct and iterative methods for large sparse linear systems. • Eigenvalue computation and optimization. • Large-scale nonlinear and semidefinite programming. • Effect of round-off errors, stopping criteria, embedded iterative procedures. • Optimization issues for matrix polynomials • Fast matrix computations. • Compressed/sparse sensing • PDE-constrained optimization • Distributed computing and optimization • Applications and real time optimization Invited Speakers Invited Speakers to be confirmed shortly. Registration Registration is currently open at https://my.ima.org.uk/ If you are an IMA Member or you have previously registered for an IMA conference, then you are already on our database. Please “request a new password” using the email address previously used, to log in. Call for Papers and Mini-Symposiums Mini-symposium proposals and contributed talks are invited on all aspects of numerical linear algebra and optimization. Mini-symposium proposals should be submitted to conferences@ima.org.uk by 31 January 2022. A mini-symposium consists of up to four speakers. For emerging topics the mini-symposium can be extended to at most two sessions on a single topic (maximum eight speakers). Organisers will be advised of acceptance by 14 February 2022. Contributed talks and mini-symposia talks will be accepted on the basis of a one page extended abstract which should be submitted by 28 February 2020 online at http://online.ima.org.uk/ or by e-mail to conferences@ima.org.uk. Authors will be advised of acceptance by 31 March 2022. A book of abstracts will be made available to delegates at the conference. Key deadlines Mini-symposia proposals: 31 January 2022 Notification of acceptance of mini-symposia: 14 February 2022 Abstract submission: 28 February 2022 Notification of acceptance of abstracts: 31 March 2022 Authors will be advised of acceptance by 31 March 2022. A book of abstracts will be made available to delegates at the conference.

Early Bird Conference Fees IMA/SIAM Member - £395.00 Non IMA/SIAM Member - £450.00 IMA/SIAM Student - £215.00 Non IMA/SIAM Student - £225.00 Conference Fees will increase by £20 on 22 May 2022 Day Delegate rate: A Day Delegate rate is also available for this Conference if you would like to attend one of the scheduled Conference days. If you would like to find out more information about our Day Delegate rate, please contact us at conferences@ima.org.uk

Accommodation The IMA have booked accommodation at Edgbaston Park Hotel on hold for delegates on a first-come, first-serve basis. The room is £90 Single occupancy, B&B which will be available to book until 16/05/2022. If you are interested in booking at this rate, please contact the Conferences Department for the booking code.

Organising Committee Michal Kocvara, University of Birmingham (co-chair) Daniel Loghin, University of Birmingham (co-chair) Coralia Cartis, University of Oxford Nick Gould, Rutherford Appleton Laboratory Philip Knight, University of Strathclyde Jennifer Scott, Rutherford Appleton Laboratory Valeria Simoncini, University of Bologna Contact information For general conference queries please contact the Conferences Department, Institute of Mathematics and its Applications, Catherine Richards House, 16 Nelson Street, Southend-on-Sea, Essex, SS1 1EF, UK. E-mail: conferences@ima.org.uk Tel: +44 (0) 1702 354 020

## July 2022

### Park City Mathematics Institute: Number theory informed by computation

Meeting Type: conference and summer school

Contact: Bjorn Poonen