Frédéric Déglise

Motives and motivic homotopy

About

My research lies at the intersection of algebraic topology and algebraic geometry. It primarily focuses on the theory of mixed motives following Vladimir Voevodsky, intersection theory, and motivic cohomology. This theory fully integrates into the theory of topos and Grothendieck's six operations formalism.

Secondly, and more broadly, the theory of motivic homotopy extends the framework of homotopy of topological spaces to that of schemes. In its stable variant, it provides a framework for the study of cohomologies, of mixed (Weil) cohomologies, of absolute cohomologies in Alexander Beilinson's terminology like syntomic cohomology, but also for the theory of orientation, characteristic classes, and Gysin morphisms.

All these theories find their natural expression and full realization in the theory of higher homotopy developed by numerous mathematicians: Grothendieck, Quillen, Joyal, and Lurie. My companions and guides in this field have been Denis-Charles Cisinski and Bertrand Toën.

More details:
Photo of Frédéric Déglise

Current Projects and Roles

Local coordinator of the MSCA research project (nb. 101168795): ReMoLD, coordinated by Jacob Scholbach.

Former Principal Investigator of the ANR research project (ANR-21-CE40-0015), with Adrien Dubouloz (IMB leader): Motivic homotopy, quadratic invariants and diagonal classes (completed project)

Former Principal Investigator of the ISITE-BFC Project ANR-lS-IDEX-OOOB (2018-2021): Motivic Invariants of Algebraic Varieties

Events

Events 2026:

  • 16-17/06/2026: AI, Proof and Formalization Days, workshop, ENS de Lyon (France), organizers: Frédéric Déglise, Stéphane Gaussent, Philippe Malbos, Véronique Maume-Deschamps, Sophie Morel, Filippo Nuccio.
    Day 1: Experience and critical feedback.   Day 2: Verification and formalization.
    Speakers include: Mathurin Massias, Omar Fawzi, Ivan Nourdin, Frédéric Marbach, Cyril Cohen, Xavier Roblot, Theo Stoskopf, María Inés de Frutos-Fernández.

Events 2025:

  • 18/11-19/11/2025: Ending conference HQDIAG, Institut Fourier (Grenoble), organizers: Jean Fasel, Frédéric Déglise, Adrien Dubouloz.
  • 28/07-01/08/2025: Motives and Arithmetic Geometry, Conference, TU Darmstadt (Germany), organizers: Tom Bachmann, Sabrina Pauli, Timo Richarz, Fabio Tanania.

Events 2024:

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