8 mar 2023 -- 14:00

Università degli Studi di Milano-Bicocca

As a part of "Geometry & Topology seminars at Unimib", it is our pleasure to announce the second speaker: Lorenzo Ruffoni, (Tufts University). The speaker will deliver the talk online via Webex platform and the meeting will be streamed also in room 3014, at the building U5-Ratio, Università degli Studi di Milano Bicocca.

Link:

https:/unimib.webex.com*unimib*j.php?MTID=ma78d63607486c4669ebb7039fbad5bec

Meeting number (access code): 2740 850 6296

Meeting password: YTinwMmU353 (98469668 from phones)

**Abstract.**

Every surface admits a metric of constant curvature. Similarly, every 3-manifold can be decomposed into pieces that admit a geometric structure locally modeled on a homogeneous space. In both cases, the most common model is the real hyperbolic space, and each model geometry can be realized inside the real projective space. On the other hand, in dimension at least 4 there are smooth manifolds that cannot be modeled on the real projective space. Previously known examples of such “non-geometric” manifolds are small, in the sense that their fundamental groups are finite or virtually cyclic. In this talk I will show how to construct examples in dimension at least 5 whose fundamental groups are non-elementary Gromov hyperbolic groups.