We organize an Oberwolfach Seminar on Topological Cyclic Homology and Arithmetic. The purpose of the seminar is to introduce the higher algebra refinements of determinant and trace, namely, algebraic K-theory and topological cyclic homology, along with their budding applications in arithmetic geometry and number theory. In particular, we will use these ingredients to build Clausen's Artin map from K-theory of locally compact topological R-modules to the dual of his Selmer K-theory of R, and explain that for R a finite, local, or global field, this implies Artin reciprocity. If you wish to participate, please follow the instructions described here to register at ag@mfo.de by August 11, 2019.

The Canadian Mathematical Society (CMS) invites the mathematical community to the 2019 CMS Winter Meeting in Toronto, Ontario from December 6-9. All meeting activities are taking place at the Chelsea Hotel. Four days of awards, mini courses, prize lectures, plenary speakers, and scientific sessions. Early Bird Registration ends October 31st. Registration closes November 15. CMS invites all speakers to submit an abstract for their session or contributed paper. Note: You are now required to register for the meeting before you can submit an abstract. Grants are available to partially fund the travel and accommodation costs for bona fide graduate students at a Canadian or other university.

The Banff International Research Station will host the "Equivariant Stable Homotopy Theory and p-adic Hodge Theory" workshop in Banff from March 1 to March 06, 2020.

Algebraic topology has had a long and fruitful collaboration with algebraic geometry, with each providing techniques and problems to the other. This workshop is aimed at an exciting, evolving incarnation of this story: applications of equivariant stable homotopy to number theory. Recent work on the foundations of equivariant stable homotopy theory (starting with the Hill--Hopkins--Ravenel work on the Kervaire invariant one problem) and Lurie's development of the foundations of ''derived algebraic geometry'' now allows systematic exploration and organization of ''equivariant derived algebraic geometry''. This allows us to do ordinary algebraic geometry in commutative ring spectra.

New foundations in this area have been spectacularly applied to phenomena seen in the trace methods approach to computing algebraic K -theory. For instance, although the theory of equivariant commutative ring spectra was described decades ago, few of the subtleties in the theory were understood or explored. The modern approaches to computing algebraic K-groups step through equivariant commutative ring spectra via the natural S1-action on topological Hochschild homology. Ongoing and transformative work by Bhatt--Morrow-Scholze in p-adic Hodge theory uses cyclotomic spectra and therefore subtle equivariant information. This workshop, at the vanguard of work in this area, seeks to bring together experts in algebraic topology, (derived) algebraic geometry, and number theory to explore these exciting new connections.

This Spring School will gather together PhD students and junior researchers who use category-theoretic ideas or techniques in their research. It will provide a forum to learn about important themes in contemporary category theory, both from experts and from each other.

Three invited speakers will each present a three-hour mini-course, accessible to non-specialists, introducing an area of active research. There will also be short talks contributed by PhD students and postdocs, and a poster session.

The focus of the Spring School is on aspects of pure category theory as they interact with research in other areas of algebra, geometry, topology and logic. Any "categorical thinker" - that is, any mathematician whose work makes use of categorical ideas - is welcome to participate.

Arithmetic groups provide a fruitful link between various areas, such as geometry, topology, representation theory and number theory. Methods from geometry and topology hinge on the fact that arithmetic groups are lattices in Lie groups, whereas the theory of automorphic forms establishes a connection to representation theory and number theory. This interplay is especially intriguing in the setting of hyperbolic 3-manifolds. Indeed many conjectures in 3-manifold theory tend to be much more accessible for hyperbolic 3-manifolds whose fundamental groups are arithmetic, and conversely such manifolds provide the simplest set-up in which some of the most exciting new phenomena in the Langlands program can be studied. This conference will bring together researchers with various backgrounds around links between number theory and 3-manifolds. Central topics of the conference are the cohomology of arithmetic groups, the relation between torsion and L²-torsion, profinite invariants of 3-manifolds, and number theoretic ramifications.

The Mathematics Research Communities program, run by AMS, is a great opportunity for young researchers to get involved in new research projects. It is a professional development program offering a chance to be part of a network. The program is described at http://www.ams.org/programs/research-communities/mrc-20 .

Marni MISHNA, Stephen MELCZER, Robin PEMANTLE are organizing a MATHEMATICAL RESEARCH COMMUNITY the week of May 31 - June 6, 2020 on the theme of Combinatorial Applications of Computational Geometry and Algebraic Topology. Yuliy BARYSHNIKOV and Mark WILSON will be assisting as well in the running of the workshop and the applied mathematics mentoring activities.

A brief description of MRC is at the site: https://www.ams.org/programs/research-communities/2020MRC-CompGeom . It is a great chance to learn some new techniques and crossover to a new community. Note the cross-disciplinary nature: the topic draws on combinatorics, singularity theory, algebraic topology, and computational algebra.

Young researchers who will be between -2 and +5 years post Ph.D. in Summer 2020 are encouraged to apply.

Applications are being accepted from now through February at the site https://www.mathprograms.org/db/programs/826 .

Andrew Ranicki and his theory of algebraic surgery played a central role in linking manifold theory, algebraic K-theory, and its close cousin L-theory. These areas have seen great developments and advances in the last decade from distinct research communities. This workshop will bring together mathematicians working on the topology of high-dimensional manifolds and their automorphisms with those working on the algebraic K-theory (and its cousins hermitian K-theory and L-theory) of rings and ring spectra, in order to share recent progress in these areas and kindle a fresh interaction between them.

See conference website

The goal of this summer school is to introduce participants to modern tools used in the study of fixed point theory in algebraic topology and homotopy theory. The workshop will be centered around mini-courses whose goal will be to introduce and apply tools such as categorical approaches to duality, spectra and trace methods in algebraic K-theory to the study of classical fixed point theory.

The intended audience for this summer school should be familiar with the material in Hatcher (except the appendices). This reflects our goal that the school be accessible to second and third year students with an interest in algebraic topology from any PhD granting institution. The school will be structured around a few mini-courses which will run in an active-learning style.

Scientific Leaders

Jonathan Campbell, Vanderbilt University

Inbar Klang, École Polytechnique Fédérale de Lausanne

Kate Ponto, University of Kentucky

Cary Malkiewich, Binghamton University

John Lind, California State Chico

Sarah Yeakel, University of Maryland

Inna Zakharevich, Cornell University

Transchromatic phenomena appear in a variety of contexts. These include stable and unstable homotopy theory, higher category theory, topological field theories, and arithmetic geometry. The aim of the conference is to bring together people from all of these areas in order to understand the relationship between each others work and to further demystify the appearance of transchromatic patterns in such disparate areas.

Homotopical and higher categorical methods have seen increasing importance in mathematics, both as foundations and as computational tools. In fact, such methods merge two apparently distinct goals: understanding geometrical forms and classifying mathematical structures. This conference aims at gathering together under this perspective geometers in a rather broad sense. It seeks to foster the applications of these higher methods in the interplay between homotopy theory, arithmetic, and algebraic geometry.

The conference is supported by the SFB1085 "Higher Invariants -Interactions between Arithmetic Geometry and Global Analysis"