Cari tutti,

Giovedì 22 Febbraio alle 15:00 presso l' aula N del Polo Fibonacci di
Pisa si terrà il Seminario dei Baby-Geometri di Carlo Collari (IMT-INDAM)
dal titolo:

"On concordance and related problems"

di cui riporto l'abstract:

"A knot is a connected compact smooth sub-manifold of $\mathbb{S}^3$ (more
in general in a three manifold, but we will be interested only in
$\mathbb{S}^3$). Two knots are \emph{concordant} if they bound a properly
embedded cylinder in $\mathbb{S}^3 \times I$. It turns out that the knots
up to concordance form an Abelian group with respect to the connected sum.
The study of the concordance group of knots is a central topic in knot
theory, and low dimensional topology in general. There are quite some
problems related to the study of this group; for instance, computating the
slice genus of a knot or understanding if a given knot is concordant to a
specific type of knot (e.g. alternating, quasi alternating etc.).
Originally, these problems have been tackled with classical invariants
(e.g. signatures), or reduced to a more algebraic framework (e.g. the
study of the algebraic concordance group). These methods are still in use
and provide useful information on the concordance group, however with the
introduction of link homologies new invariants came up.

In this seminar, after a general introduction to the concordance group,
and to the above mentioned problems, we will talk about a large family of
concordance invariants defined from link homologies. In particular, I wish
to highlight some features of these invariants, their properties and some
of their "faults". Time permitting, I will also spend few words on the
generalisation of these invariants to links (which is a part of joint work
with Alberto Cavallo)."

Vi segnalo in anticipo che Lunedì 26 Febbraio, in Sala Seminari alle
16.30, si terrà il seminario di Francesco Panelli (Università degli studi
di Firenze). A breve vi invierò titolo e abstract.


Tutti gli interessati sono invitati a partecipare.

Per saperne di più sui prossimi seminari scrivete a

babygeometri@cs.dm.unipi.it

o consultate la nostra pagina web:

http://people.dm.unipi.it/babygeometri/


Saluti,

Edoardo Fossati, Giulio Belletti e Marco Moraschini