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Hodge filtration on local cohomology and applications

HARVARD-MIT ALGEBRAIC GEOMETRY

March 30, 2021      3:00 pm
Speaker: Mihnea Popa - Harvard University

This describes joint work in progress with M. Mustata, in which we study the filtration on local cohomology sheaves induced by their natural mixed Hodge module structure. Special properties of...
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Lie algebras, deformations, and Galois theory in characteristic p.

HARVARD-MIT ALGEBRAIC GEOMETRY

March 16, 2021      4:30 pm
Speaker: Lukas Brantner

We introduce a derived version of Lie algebras in characteric p and describe two recent applications: first, we use them to classify infinitesimal deformations, generalising the Lurie-Pridham theorem in characteristic...
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On extension of pluricanonical forms for Kaehler families

HARVARD-MIT ALGEBRAIC GEOMETRY

March 9, 2021      3:00 pm
Speaker: Mihai Paun - University of Bayreuth

We will report on a recent joint work with Junyan Cao, cf. arXiv:2012.05063. The main topics we will discuss are revolving around the extension of pluricanonical forms defined on the...
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Decomposition theorem for semisimple local systems

HARVARD-MIT ALGEBRAIC GEOMETRY

March 2, 2021      3:00 pm
Speaker: Ruijie Yang - Stony Brook University

In complex algebraic geometry, the decomposition theorem asserts that semisimple geometric objects remain semisimple after taking direct images under proper algebraic maps. This was conjectured by Kashiwara and is proved...
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On the proportion of transverse-free curves

HARVARD-MIT ALGEBRAIC GEOMETRY

February 16, 2021      3:00 pm
Speaker: Shamil Asgarli

Given a smooth plane curve C defined over an arbitrary field k, we say that C is transverse-free if it has no transverse lines defined over k. If k is...
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The cohomology of moduli of curves at infinite level

HARVARD-MIT ALGEBRAIC GEOMETRY

December 8, 2020      3:00 pm
Speaker: Emanuel Reinecke - IAS

Moduli spaces of curves admit finite covers by moduli spaces which parametrize curves together with so-called level structures. In my talk, I will discuss how the cohomology of these spaces...
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Positroid varieties and q,t-Catalan numbers

HARVARD-MIT ALGEBRAIC GEOMETRY

December 1, 2020      3:00 pm
Speaker: Thomas Lam - University of Michigan

Positroid varieties are subvarieties of the Grassmannian obtained by intersecting cyclic rotations of Schubert varieties.  We show that the "top open positroid variety" has mixed Hodge polynomial given by the...
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Top weight cohomology of A_g

HARVARD-MIT ALGEBRAIC GEOMETRY

November 17, 2020      3:00 pm
Speaker: Gwyneth Moreland - Harvard University

I will discuss recent work on computing the top weight cohomology of A_g for g up to 7. We use combinatorial methods coming from the relationship between the top weight...
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