buondi',

vorrei ricordarvi che oggi alle 14.30 c'e' come sempre il seminario di geometria: lo speaker e' Yuyu Koda (Tokohu University), che siamo lieti di ospitare nel nostro dipartimento per i prossimi due anni.

Bruno

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MERCOLEDI' 19 SETTEMBRE 2012 14:30-15:30, Sala Seminari (Dip. Matematica)

SEMINARI DI GEOMETRIA Primitive disk complexes and genus two Goeritz groups of all lens spaces Yuya Koda (Tokohu University)

The Goeritz group of a Heegaard splitting of a closed orientable 3-manifold is the group of isotopy classes of orientation-preserving automorphisms of the 3-manifold that preserve the Heegaard splitting. We review standard facts and histories on the topic and then we provide presentations of the Goeritz groups of the genus two Heegaard splittings of all lens spaces by studying the detailed structure of the primitive disk complexes. If time permits, we discuss an application to the space of Heegaard splittings. This is a joint work with Sangbum Cho.

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Dipartimento di Matematica Largo Pontecorvo 5 56127 Pisa, Italy

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