Carə tuttə,
Il seminario di geometria di questa settimana si terrà eccezionalmente domani martedì 26 Marzo in Saletta Riunioni alle 14.30. Tanushree Shah (Universität Wien) parlerà di "Contact structures on 3-manifolds". Di seguito l'abstract.
I will start by introducing contact structures. They come in two flavors: tight and overtwisted. Classification of overtwisted contact structures is well understood as opposed to tight contact structures. Tight contact structures have been classified on very few 3-manifolds. We will look at what more classification results can we hope to get using the current techniques and what is far-fetched.
Le informazioni sui prossimi seminari si trovano sul sito<https://www.dm.unipi.it/en/seminars/?category=653b522f8f0af760bdc42729>.
Vi aspettiamo!
Buona giornata,
Filippo, Giovanni e Giuseppe
Carə tuttə,
Giovedì 21 Marzo ci saranno due seminari di geometria, entrambi in Aula Seminari.
Alle 11, Clara Löh (Universität Regensburg) parlerà di "A quadratic lower bound on the number of minimal gedesics". Di seguito l'abstract.
A minimal geodesic on a Riemannian manifold is a geodesic line that lifts to a globally isometric geodesic line on the universal covering. Bangert proved that there is a lower bound for the number of geometrically distinct minimal geodesics of closed Riemannian manifolds that is linear in the first Betti number, using the stable norm ball on the first homology. We refine this method to obtain a quadratic lower bound. This is based on joint work with Bernd Ammann (Regensburg).
Alle 14.30, Keegan Boyle (University of British Columbia) parlerà di "Alexander polynomials and symmetric knots". Di seguito l'abstract.
In this talk I will discuss the extra topological information which can be extracted from the Alexander polynomial of a knot in S^3 in the case where there are certain types of symmetry on the knot. Specifically, I will discuss 2-periodic, strongly invertible, and strongly negative amphichiral knots. I will mention join work with Ahmad Issa, with Wenzhao Chen, and with Nicholas Rouse and Ben Williams.
Le informazioni sui prossimi seminari si trovano sul sito<https://www.dm.unipi.it/en/seminars/?category=653b522f8f0af760bdc42729>.
Vi aspettiamo!
Buona giornata,
Filippo, Giovanni e Giuseppe
