Dear all, I would like to announce a talk by Prof. Riccardo Piergallini from University of Camerino, which take place on Friday 11 February at 15:00. Title: Algebra of 4-dimensional of 2-handlebodies Abstract: TBA Venue: Aula Seminari, Dipartimento di Matematica e Geoscienze, via Valerio 12/1 Kind regards, Daniele Zuddas