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- Enrica Floris: Singularities in the MMP
We will survey the different definitions of singularities of pairs
(terminal, canonical, klt, lc) and give many examples illustrating the
subtleties of the various definitions. We will prove some geometric
properties and explain how the singularities play a role in vanishing
theorems.
- Anne Moreau: Vertex algebras and singularities
In this series of lectures, we will explain how the geometry of
certain Poisson varieties, their singularities and their arc spaces,
can be used to investigate some interesting problems on vertex
algebras. Among the topics, we will explore remarkable connections
between the characters of some vertex algebras (in the framework of
W-algebras) and the Hilbert series of arc spaces associated with
certain Poisson varieties.
Reference for the lectures
- Mircea Mustaţă: Mixed Hodge modules and singularities
Lecture I: V-filtrations and b-functions
Lecture II: The Hodge filtration on local cohomology
Lecture III: The minimal exponent, the Hodge filtration, and the Du Bois complex
Abstract: D-modules on a smooth complex algebraic variety X are
sheaves of modules over the sheaf of differential operators on X.
Saito's theory of Hodge modules provides a functorial framework for
doing Hodge theory, in which the basic objects are D-modules endowed
with a canonical good filtration (the Hodge filtration). In this
lecture series, we will discuss the connection between the Hodge
filtration on the localization O_X[1/f] and the singularities of the
hypersurface defined by f.
Lecture I: A key notion in the theory of Hodge modules is that of
V-filtration, a concept introduced by Malgrange and Kashiwara. Its
main feature is that it provides the D-module counterpart for the
notions of nearby and vanishing cycles, and, as such, it provides
invariants of singularities that are interesting in their own
right. In the first lecture, we will discuss the V-filtration and its
connection with the notion of b-function (or Bernstein-Sato
polynomial).
Lecture II: After a brief introduction to Hodge modules, we will
discuss the Hodge filtration on the localization O_X[1/f] and its
connection with the V-filtration and the b-function associated to f.
If time permits, we will discuss the more general case of Hodge
filtrations on local cohomology sheaves.
Lecture III: We will review the Du Bois complex of complex algebraic
varieties and then discuss its connection with Hodge modules and, in
particular, to the minimal exponent of hypersurface singularities.
Prerequisites: Some familiarity with D-module theory would be useful,
at least to provide context and motivation. For example, the overview
in Chapter I of the notes available at
https://websites.umich.edu/~mmustata/NotesTokyo.pdf
should be enough for this purpose.