Search results for " Torelli"

Tragedia e senso del tragico in Torquato Tasso e nel secondo Cinquecento

Scopo della presente dissertazione è quello di indagare la tragedia e il tragico, in Torquato Tasso e negli autori del Secondo Cinquecento, attraverso un’indagine a largo spettro che, a partire dagli scritti che teorizzano le regole proprie del genere tragico (trattati, commentari, lettere etc.) e attraverso la delineazione di un macrotema utile a definirne gli elementi più caratteristici, si conclude con un’ultima sezione mirante a indagare il “senso del tragico”. La tesi, infatti, si divide in tre sezioni: nella prima s’indaga il significato di Tragedia nel secondo Cinquecento attraverso la trattatistica, nella seconda si affronta un macro-tema, le amicizie tragiche, volto a sunteggiare i…

Equivalence relations among homology 3-spheres and the Johnson filtration

2021

The Torelli group of a surface consists of isotopy classes of homeomorphisms of this surface acting trivially at the homological level. The structure of the Torelli group can be approached by the study and the comparison of two filtrations of this group: its lower central series, and the "Johnson" filtration, given by the kernels of the natural actions on the successive nilpotent quotients of the fundamental group of the surface. It is now known that there are, via the notion of "Heegaard splittings", rich interactions between this 2-dimensional study and the study of some 3-manifolds topological invariants: we refer here precisely to the so-called "finite-type" invariants. In this PhD, we …

Automorphisms of right-angled Artin groups

2012

The purpose of this thesis is to study the automorphisms of right-angled Artin groups. Given a finite simplicial graph $\Gamma$, the right-angled Artin group $G_\Gamma$ associated to $\Gamma$ is the group defined by the presentation whose generators are the vertices of $\Gamma$, and whose relators are commutators of pairs of adjacent vertices. The first chapter is intended as a general introduction to the theory of right-angled Artin groups and their automorphisms. In a second chapter, we prove that every subnormal subgroup of $p$-power index in a right-angled Artin group is conjugacy $p$-separable. As an application, we prove that every right-angled Artin group is conjugacy separable in th…