A pseudo-Riemannian metric is said to be Einstein if its Ricci tensor is a constant multiple of the metric. Bi-invariant metrics on simple Lie groups are examples; more generally, there are several known constructions to obtain homogeneous Einstein metrics, i.e. invariant under the transitive action of a group.…
Categoria evento: Geometry Seminar
Equazioni di Seiberg-Witten e 3-varietà iperboliche – Francesco Lin (Columbia)
Un interessante problema aperto in topologia in dimensione bassa è quello di capire possibili interazioni fra l’omologia di Floer e gli invarianti geometrici di varietà iperboliche. …
Pseudo-Kähler geometry of properly convex projective structures in a linear case – Nicholas Rungi (SISSA)
In this talk we will define a pseudo-Kähler structure on the deformation space of properly convex projective structures over the 2-dimensional torus.…
Simplicial volume and aspherical manifolds – Marco Moraschini (Università di Bologna)
Simplicial volume is a homotopy invariant for compact manifolds introduced by Gromov in the early 80s. It measures the complexity of a manifold in terms of singular simplices.…
Coarse homology theories – Luigi Caputi (University of Aberdeen)
Coarse spaces, first introduced by J. Roe for studying index-type theorems, have recently found applications also in K-theory and assembly map conjectures. The main tool in such applications is given by coarse homology theories, homological…
Coarse homology theories – Luigi Caputi
Abstract…
An arithmetic, hyperbolic, rational homology 3-sphere that bounds geometrically – Leonardo Ferrari (Neuchatel (Svizzera))
In this seminar, we’ll introduce Davis and Januszkiewicz combinatorial techniques for building manifolds from right-angled polytope, as well as some topological properties inherited by these manifolds. We’ll then present some obstructions to…
Multipath homology and the path poset. – Carlo Collari (Università di Pisa)
The aim of this talk is to present some homology theories for graphs (and, in particular, multipath homology), describe their mutual relationship, and see how these theories are connected with other homology theories (i.e. homology theories for…
Cusps of Hyperbolic 4-Manifolds and Rational Homology Spheres – Leonardo Ferrari (Università di Pisa)
By Margulis’ Lemma, a finite-volume complete hyperbolic n-manifold has a finite number of ends called cusps, each of which is diffeomorphic to the product of a flat (n-1)-manifold with the half-line. These flat manifolds are called cusp sections,…
Obstructing sliceness of knots through branched covers – Andras Stipsicz (Alfréd Rényi Institute of Mathematics, Budapest)
slice knots (bounding smooth disks in the 4-space) play an important role in knot theory. They can be studied through examining the branched cover of the three-sphere along the given knot. In the lecture we describe two results around these…