[geometry-ml:02420] MS seminar at Kavli IPMU

[Todor Milanov]

Dear all, 

I would like to announce the following two seminars at Kavli IPMU

1) Tathagata Basak	(Iowa State U)
Date: Tue, Aug 04, 2015, 13:15 - 14:45
Place: Seminar Room A, Kavli IPMU

Finding nice generators for braid-like groups

Let X be either the complex affine space or the complex hyperbolic space. Let G be a discrete group acting on X by isometries. Let D be the co-dimension one strata of the set of points of X that have non-trivial stabilizer in G. We shall describe a theorem that lets us find ``nice” generators for the fundamental group of (X - D)/G in some cases. We shall apply the this theorem  to a particular group G acting on the 13 dimensional complex ball X. This particular group action is of interest to us because of the ``Monstrous proposal” conjecture that related the the 13 dimensional complex hyperbolic orbifold (X-D)/G and the monster simple group. This is joint work with Daniel Allcock.

2) Oren Ben-Bassat	(Oxford)
Date: Wed, Aug 05, 2015, 13:15 - 14:45
Place: Seminar Room B, Kavli IPMU

Title: Multiple Lagrangian Intersections

Abstract: Joyce and others have used shifted symplectic geometry to define Donaldson--Thomas Invariants. This kind of geometry naturally appears on derived moduli stacks of perfect complexes on Calabi-Yau varieties. One wonderful feature of shifted symplectic geometry (developed by Pantev, Toën, Vaquié and Vezzosi) is that fibre products (i.e. intersections) of Lagrangians automatically carry Lagrangian structures. Using a strange property of triple intersections from arXiv:1309.0596, this extra structure can be organized into a $2$-category. One can also speculate on the relationship of this $2$-category with TQFTs, algebraic versions of the Fukaya categories, infinity categories of Lagrangians and the gluing of stacks of matrix factorizations. This is joint work with Lino Amorim (Oxford).

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Todor Eliseev Milanov
Associate Professor 
Kavli IPMU,  Japan

todor.milanov ＠ ipmu.jp