Department of Mathematics

Indian Institute of Science

Bangalore 560 012

 

SEMINAR

 

Speaker

:

 Mr. Dheeraj Kulkarni
Affiliation : IISc, Bangalore.

Subject Area

:

Mathematics

 

Venue

:

Department of Mathematics, Lecture Hall I

 

Time

:

11.00 a.m.-12.00 p.m.

 

Date  

:

July13, 2012 (Friday)

Title

:

"Relative Symplectic Caps, 4-Genus and Fibered Knots"
Abstract

:

The $4$-genus of a knot is an important measure of complexity, related to the unknotting number. A fundamental result used to study the $4$-genus and related invariants of homology classes is the \emph{Thom Conjecture}, proved by Kronheimer-Mrowka, and its symplectic extension due to Ozsvath-Szabo, which say that \textit{closed} symplectic surfaces minimize genus. Suppose $(X, \omega) $ is a symplectic 4-manifold with contact type bounday $\partial X $ and $\Sigma $ is a symplectic surface in $X$ such that $\partial \Sigma $ is a transverse knot in $\partial X $. In this talk we show that there is a closed symplectic 4-manifold $Y $ with a closed symplectic submanifold $ S$ such that the pair $(X, \Sigma) $ embeds symplectically into $(Y, S) $. This gives a proof of the relative version of Symplectic Thom Conjecture. We use this to study 4-genus of fibered knots in $\mathbb{S}^3$. We also discuss the symplectic convexity of unit circle bundle in a Hermitian holomorphic line bundle over a Riemann surface. This is joint work with Prof. Siddhartha Gadgil.