Some geometric constructions of link homology
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Tue, 28/04/2009 15:45 |
Geordie Williamson (Oxford) |
Algebraic and Symplectic Geometry Seminar  |
L3 |
| Triply graded link homology (introduced by Khovanov and Rozansky) is a categorification of the HOMFLYPT polynomial. In this talk I will discuss recent joint work with Ben Webster which gives a geometric construction of this invariant in terms of equivariant constructible sheaves. In this framework the Reidemeister moves have quite natural geometric proofs. A generalisation of this construction yields a categorification of the coloured HOMFLYPT polynomial, constructed (conjecturally) by Mackay, Stosic and Vaz. I will also describe how this approach leads to a natural formula for the Jones-Ocneanu trace in terms of the intersection cohomology of Schubert varieties in the special linear group. | |||