buondì,

vi annuncio il seminario di geometria di domani, al quale siete tutti invitati. a presto, Bruno

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Wednesday, April 8, 2015 Ora Inizio: 16:00 Aula: Sala Seminari (Dip. Matematica)

SEMINARI DI GEOMETRIA

Relatore: Antonio De Capua (University of Oxford)

Titolo: Hyperbolic volume of links, via pants graphs and train tracks

Abstract: A result of Jeffrey Brock states that, given a hyperbolic 3-manifold which is a mapping torus over a surface S, its volume can be expressed in terms of the distance induced by the monodromy map in the pants graph of S. This is an abstract graph whose vertices are pants decompositions of S, and edges correspond to some sort of 'elementary alterations' of those. Brock's theorem motivates investigation about distances in the pants graph; in particular we generalise a result of Masur, Mosher and Schleimer that train track splitting sequences (which will be defined during the talk) induce quasi-geodesics in the marking graph. This will be the core piece of a volume estimate for complements of closed braids in the solid torus.