Speaker: Reyer Sjamaar

Title:

Convexity properties of presymplectic Hamiltonian actions

Abstract:

I will present a generalization of the convexity theorem of Atiyah, Guillemin-Sternberg and Kirwan, to Hamiltonian Lie group actions on presymplectic manifolds.  The result implies convexity theorems for actions on contact manifolds, cosymplectic manifolds, as well as certain symplectic "generalized manifolds".  This is joint work with Yi Lin.

Speaker: Chi-Kwong Fok

Title: Equivariant formality of homogeneous spaces

Abstract: In equivariant topology, equivariant formality, first defined by Goresky-Kottwitz-MacPherson in cohomological terms, is a desirable property of spaces with group actions. In this talk we will examine equivariant formality from the perspective of K-theory. This approach is inspired by Harada-Landweber's work on K-theory of symplectic manifolds. We will also apply K-theoretic equivariant formality to give a characterisation of equivariant formality of compact homogeneous spaces G/K with isotropy action of K. Part of this talk is based on joint work with Jeffrey Carlson. 

Speaker:Hsuan-Yi Liao 

Title: Kontsevich–Duflo theorem 

Abstract: In late 1990’s, Kontsevich revolutionized the field of deformation quantization with his formality theorem. Amazingly, it turned out that the classical Duflo theorem is another of the many consequences of Kontsevich’s formality construction. Based Kontsevich’s idea, one can get Duflo-type theorems in different contexts. In this talk, I’ll explain our version of Kontsevich–Duflo theorem for a Lie algebroid pair (i.e. a Lie algebroid together with a Lie subalgebroid).