Buondì,
Vi annuncio che oggi (alle 16) e giovedì prossimo (sempre alle 16) ci
saranno due seminari sulle 4-varietà. Seguono più informazioni.
A presto,
Bruno
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05-Oct-2017 - 16:00
Sala Seminari (Dip. Matematica)
Rohlin’s theorem and non-simply connected 4-manifolds
Danny Ruberman (Brandeis University)
Most applications of gauge theory in 4-dimensional topology are concerned
with simply-connected manifolds with non-trivial second homology. I will
discuss the opposite situation, first describing the classical Rohlin
invariant for manifolds with first homology = Z and vanishing second
homology. I will give an interpretation in terms of a Seiberg-Witten
theory, with an unusual index-theoretic correction term. I will discuss
recent work with Jianfeng Lin and Nikolai Saveliev giving a new formula for
this invariant in terms of monopole homology.
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12-Oct-2017 - 16:00
Sala Seminari (Dip. Matematica)
On corks with low shadow-complexity
Hironobu Naoe (Tohoku University, Japan)
A cork is a contractible Stein domain that gives arise to exotic pairs of
4-manifolds. The first example was found by Akbulut. It is known that any
two exotic, simply-connected, closed 4-manifolds are related by a cork
twist. We show that there are no corks having shadow-complexity zero. We
also show that there are infinitely many corks having shadow-conplexity 1
and 2.