Toledo Invariants of Quantum Representations

par Prof. Bertrand Deroin (CNRS & Université de Cergy)

lundi 14 févr. 2022, 16:00 → 17:15 Europe/Paris

Amphithéâtre Léon Motchane (IHES)

Quantum representations form a family of representations of modular groups of surfaces with values in projective pseudo-unitary groups PU(p,q), sending Dehn twists to finite-order elements. Toledo invariants of these representations, and more general characteristic classes, extend to cohomology classes defined on the Deligne-Mumford compactification of moduli spaces, defining cohomological field theories (CohFT). We will give explicit formulae for the Toledo part of the latter in some cases, including Fibonacci quantum representations. This allows to construct/recover complex hyperbolic structures on some moduli spaces. Work in progress with Julien Marché.

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IHES Covid-19 regulations:

- all the participants who will attend the event in person will have to keep their mask on in indoor spaces
and where the social distancing is not possible;
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without it;
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- Over 25 persons in the conference room, every participant will be asked to provide a health pass which will
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