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Back to Algebraic Geometry Seminar: Fall 2021

Algebraic Geometry Seminar


Date: Tuesday, Nov 30, 2021

Time: 3:30PM - 4:30PM

Location: Zoom


Oishee Banerjee

HCM Bonn

Title

Filtration of cohomology via symmetric (semi)simplicial spaces

Abstract

Inspired by Deligne’s use of the simplicial theory of hypercoverings in defining mixed Hodge structures we replace the indexing category ∆ by the symmetric simplicial category ∆S and study (a class of) ∆S-hypercoverings, which we call spaces admitting symmetric (semi)simplicial filtration . For ∆S-hypercoverings we construct a spectral sequence, somewhat like the Cˇech-to-derived category spectral sequence. The advantage of working on ∆S is that all of the combinatorial complexities that come with working on ∆ are bypassed, giving simpler, unified proof of known results like the computation of (in some cases, stable) singular cohomology (with rational coefficients) and étale cohomology (with Q_l coefficients) of the moduli space of degree (n) maps (C) to a projective space, (C) a smooth projective curve of genus (g), of unordered configuration spaces, that of the moduli space of smooth sections of a fixed (g_d^r) that is (m)-very ample etc.

Algebraic Geometry

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