martedi' - 16-03-2004 (15:00 - Sala Riunioni) : Andras I. Stipsicz

Ozsvath--Szabo invariants and contact structures argomento: Geometria abstract: The study of tight contact structures on closed 3-manifolds turned out to be a very effective way for understanding certain geometric properties of the 3-manifold at hand. In the lecture we show a way to find such structures and prove their tightness in some particular cases. For example, we show that the result of almost any rational surgery on a positive torus knot admits a tight contact structure. Tightness will be proved by applying contact invariants recently introduced by Ozsvath and Szabo

martedi' - 16-03-2004 (16:00 - Sala Riunioni) : Gaspare Carbone (Universita' di Pisa) Triangolazioni decorate ed invarianti. abstract: I principi della meccanica quantistica mostrano come, nel singolo tetraedro, soltanto alcune informazioni geometriche siano essenziali. Individuata, sulla triangolazione, una decorazione compatibile con questa affermazione, mostreremo come sia possibile definire delle state sum invarianti sotto opportune mosse e come questo riproduca, nel caso puramente geometrico, l'invariante di Reshetikhin Turaev

martedi' - 16-03-2004 (16:00 - Aula O1 Polo Fibonacci) : Marcelo Epstein

On non-local Eshelby entities argomento: Fisica Matematica abstract: Adopting as a point of departure for the setting of continuum mechanics a configuration space consisting of an infinite-dimensional manifold of maps, it is shown that the concepts of stress (both mechanical and configurational) can be elegantly generalized, at least from a formal perspective, to a completely global framework. Moreover, for a special type of global behaviour (referred to as "non-local") it is possible to formulate a consistent theory of material uniformity, in spite of intuitive warnings to the contrary. Since the body is defined as a manifold with boundary, it turns out to be possible to "compare" the constitutive contributions of boundary points with interior ones. The formulation is applied to a one-dimensional situation and some preliminary inferences are made.

Giulia Curciarello Segreteria Didattica tel: 050-2213219 e-mail curciare@dm.unipi.it

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