Cari tutti, vi segnalo questa attività per il ciclo di seminari dei Baby Geometri: Lunedì 30 Aprile alle 16:30 presso l'Aula Seminari del Dipartimento di Matematica Alessio Savini(ETH Zurich - Bologna) ci parlerà di: Rigidity of real hyperbolic lattices: a "natural" approach di cui riporto l'abstract: Rigidity of lattices in semisimple Lie groups has been widely studied so far. One of the most celebrated theorem is Mostow rigidity, which states the following. Assume n bigger or equal than 3. If two complete hyperbolic n-manifolds of finite volume have isomorphic fundamental groups then they are isometric. Equivalently their fundamental groups are conjugated in the group of isometries of the hyperbolic n-space. There are several ways to prove this theorem. We will expose a proof based on the so-called natural maps, introduced by Besson-Courtois-Gallot and will try to explain the role played by the geometric/aritmetic mean inequality in the proof. Tutti gli interessati sono invitati a partecipare. Per saperne di più sui prossimi seminari scrivete a babygeometri@cs.dm.unipi.it <https://student-web1.dm.unipi.it/squirrelmail/src/compose.php?send_to=babygeometri%40cs.dm.unipi.it> o consultate la nostra pagina web: http://people.dm.unipi.it/babygeometri/ Saluti, Giulio Belletti, Edoardo Fossati e Marco Moraschini