Differential Geometry Seminar

Speaker: 
Jun Li, Univ. of Minnesota
Topic: 
Symplectic-2 spheres and the symplectomorphism group of small rational 4-manifolds

Abstract: For a rational 4-manifold $M$, reduced symplectic forms play a role since any symplectic form on $M$ is symplectomorphic to a reduced one. We give a combinatoric approach and a Lie theoretic approach to describe the normalized reduced cone for a rational 4-manifold $M$, both will be explicitly illustrated. Using this as a guidance, we see the change and persistence of the symplectomorphism group when one deforms the symplectic form.  In particular, explicit computation of $\pi_{1}(\operatorname{Ham}(M))$ will be carry out and a complete description of symplectic mapping class group will be given when Euler number of $M$ is small.

Event Date: 
November 29, 2016 - 2:30pm to 3:30pm
Location: 
B13 MLH
Calendar Category: 
Seminar