Amphithéâtre Guillaume Budé, Site Marcelin Berthelot
Open to all
-

Abstract

The logic of higher categories (or ∞-categories) is a variation of type theory, which is homotopic in nature and in which the notion of category is the primitive concept - the one that is never defined! An adequate generalization of Voevodsky's axiom of univalence makes this theory a highly expressive language, sufficiently so that it can produce its own semantic interpretations. This provides a mathematical foundation system at the heart of which the concepts of category theory and homotopy theory are implemented. A logic of logics. A semantic interpretation of this logic is produced in classical mathematics by the theory of ∞-categories as developed by Joyal and Lurie. A formulation in dependent type theory, via Riehl-Shulman theory, is the subject of a current project by Buchholtz and Weinberger. This logic makes it possible to formulate constructively many theories considered as advanced (e.g. spread cohomology of derived or non-derivative schemes, derived categories of quasi-coherent bundles) in a way close to practice. It's also a new way of apprehending logic itself, so that the distance between syntax and semantics is apparently very significantly reduced: logics are terms of a type, i.e. objects of an ∞-category.

Denis-Charles Cisinski

Denis-Charles Cisinski

Denis-Charles Cisinski est professeur de mathématiques à l'Universität Regensburg, en Allemagne. Il a occupé des postes permanents à l'université de Toulouse et à l'université Sorbonne-Paris-Nord, et est un ancien membre de l'Institut universitaire de France. Ses recherches portent sur l'algèbre homotopique, la théorie des catégories, la K-théorie et la cohomologie des schémas. Il est l'auteur de trois monographies : Les préfaisceaux comme modèles des types d'homotopie (2007), Triangulated categories of mixed motives (2019), et Higher categories and homotopical algebra (2019).

Speaker(s)

Denis-Charles Cisinski

Professor, Universität Regensburg