algebraic geometry seminar Monday October 23 at 9:30 in room 136 Sissa

[Barbara Fantechi]

A series of seminars on DT invariants will start on Monday, 9:30 in Room
136 with the talk by Carlo Scarpa (Sissa)

"Taubes' Casson Invariant and its holomorphic analogue"

Abstract: n 1985, Casson defined a topological invariant for (real) 3-folds
with the homology of the sphere; not much later Taubes gave a
gauge-theoretic construction of the Casson Invariant as a signed “virtual
count” of flat SU(2)-connections, up to gauge equivalence.
In 1998, Donaldson and Thomas proposed to use a similar approach to count
holomorphic structures on vector bundles over a Calabi-Yau 3-fold;  we
shall see that this problem has several analogies with the previous one. In
this case, however, there doesn't seem to be a differential-geometric way
of doing the virtual count. This led Thomas to consider the problem from an
algebro-geometric point of view, which will be the topic of the next
seminars.


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Mathematical Physics Sector
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public calendar: http://people.sissa.it/fantechi/cal