19 febbraio 2004

Eventi del giorno ore: 14:30:00, Centro De Giorgi:

Giuseppe Buttazzo: Tre problemi di ottimizzazione in teoria del trasporto abstract: We give a model for the deion of an urban transportation network and we consider the related optimization problem which consists in finding the desing of the network which has the best transportation performances. This will be done by introducing, for every admissible network, a suitable metric space with a distance that inserted into the Monge-Kantorovich cost functional provides the criterion to be optimized. Together with the optimal design of an urban transportation network, other kinds of optimization problems related to mass transportation can be considered. In particular we will illustrate some models for the optimal design of a city, and for the optimal pricing policy on a given transportation network. ARGOMENTO: Analisi Matematica

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ore: 15:00:00, Aula 1 Dip.di Matematica

Peter Littelmann: A Pieri-Chevalley formula for the $K$-theory of flag varieties abstract: The Chow ring of the Grassmann variety $G_{d,n}$ of $d$--dimensional subspaces of ${\bf C}^n$ has a ${\bf Z}$--basis consisting of the classes defined by the cycle represented by the Schubert variety. Let ${\cal L}$ be the ample generator of Pic~$G_{d,n}$. The classical formula of Pieri expresses the product (in the Chow ring) of the class of ${\cal L}$ with the class of a Schubert variety. In the $K$--theory of the Grassmann variety, or more generally, of a generalized flag manifold, one would like to have a similar type of formula for the product of the class of an ample line bundle and the class of the structure sheaf a Schubert variety. In the talk we will present an effective version (i.e., we provide explicit filtrations) of the combinatorial Pieri-Chevalley type formula proved by Pittie and Ram, and we discuss the close connection between what is called {\it Standard monomial theory} and an effective version of the Pieri-Chevalley type formula.

ARGOMENTO: Algebra

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ore: 15:30:00, sala Seminari

Giorgio Dalzotto: Massimo comune divisore e fattorizzazione in anelli quoziente U.F.D abstract: ARGOMENTO: Algebra

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

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