Buondì,
Con estremo ritardo vi comunico che oggi alle ore 15.30 in aula seminari
Marco Moraschini (Università di Pisa) terrà il seguente seminario:
"An introduction to ideal simplicial volume",
di cui è riportato sotto l'abstract. Tutti gli interessati sono invitati a
partecipare.
Bruno
Abstract:
The simplicial volume is a homotopy invariant of compact manifolds
introduced in 1982 by Gromov in his pioneering paper "Volume and Bounded
Cohomology". Roughly speaking, the simplicial volume measures how difficult
is to describe a manifold in terms of real singular chains.
In this talk, we will define the ideal simplicial volume, a variation of
the ordinary simplicial volume for compact manifolds with boundary. The
main difference between ideal simplicial volume and the ordinary simplicial
volume of a manifold M is that this new invariant measures the minimal size
of possibly ideal triangulations of M "with real coefficients", since ideal
simplices are now allowed to appear in representatives of the fundamental
class.
Moreover, we will show that for manifolds whose boundary components all
have an amenable fundamental group, the ideal simplicial volume coincides
with the classical one.
Finally, if we have enough time, we will discuss the precise computation of
the ideal simplicial volume of an infinite family of hyperbolic 3-manifolds
with geodesic boundary, for which the exact value of the classical
simplicial volume is not known.
This is a joint work with Roberto Frigerio