Cari tutti,

Giovedì 9 Febbraio alle 17:30 presso la Sala Riunioni del DM di Pisa si terrà il Seminario dei Baby-Geometri di Claudio Quadrelli (Università di Firenze) dal titolo:

"Knots, Galois groups and Massey products"

di cui riporto l'abstract:

"Cohomological Massey products were defined in the '50s as higher cohomology operations generalizing the cup product, to provide a ``cohomological translation'' of the Milnor invariants, which describe the higher linking properties of the knots in a link. After introducing Massey products, I will tell how they have been employed recently to understand the structure of Galois groups of fields: in particular, there are deep analogies between the Galois groups of certain extensions of Q and the fundamental groups of links (e.g., there is an arithmetic analogue of the Borromean rings!), whereas groups with ``non-vanishing'' Massey products do not occur as absolute Galois groups of fields. (No advanced knowledge in algebra -- nor in algebraic topology -- is required.)"

Tutti gli interessati sono invitati a partecipare.

Per saperne di più sui prossimi seminari scrivete ad uno degli organizzatori o consultate le pagine:

http://blog.phc.unipi.it/babygeometri/ http://gecogedi.dimai.unifi.it/seminars/ Mailing-list: babygeom@poisson.phc.unipi.it

Saluti,

Carlo Collari, Marco Moraschini e Nicoletta Tardini