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Conformal blocks and cohomology in genus 0

Prakash Belkale, Swarnava Mukhopadhyay (2014)

Annales de l’institut Fourier

We give a characterization of conformal blocks in terms of the singular cohomology of suitable smooth projective varieties, in genus 0 for classical Lie algebras and G 2 .

Connected components of the strata of the moduli spaces of quadratic differentials

Erwan Lanneau (2008)

Annales scientifiques de l'École Normale Supérieure

In two fundamental classical papers, Masur [14] and Veech [21] have independently proved that the Teichmüller geodesic flow acts ergodically on each connected component of each stratum of the moduli space of quadratic differentials. It is therefore interesting to have a classification of the ergodic components. Veech has proved that these strata are not necessarily connected. In a recent work [8], Kontsevich and Zorich have completely classified the components in the particular case where the quadratic...

Contact geometry and CR-structures on spheres

John Bland, Tom Duchamp (1995)

Banach Center Publications

A normal form for small CR-deformations of the standard CR-structure on the (2n+1)-sphere is presented. The space of normal forms is parameterized by a single function on the sphere. For n>1, the normal form is used to obtain explicit embeddings into n + 1 . For n=1, the cohomological obstruction to embeddability is identified.

Cross ratios, Anosov representations and the energy functional on Teichmüller space

François Labourie (2008)

Annales scientifiques de l'École Normale Supérieure

We study two classes of linear representations of a surface group: Hitchin and maximal symplectic representations. We relate them to cross ratios and thus deduce that they are displacing which means that their translation lengths are roughly controlled by the translations lengths on the Cayley graph. As a consequence, we show that the mapping class group acts properly on the space of representations and that the energy functional associated to such a representation is proper. This implies the existence...

Cross ratios, surface groups, P S L ( n , 𝐑 ) and diffeomorphisms of the circle

François Labourie (2007)

Publications Mathématiques de l'IHÉS

This article relates representations of surface groups to cross ratios. We first identify a connected component of the space of representations into PSL(n,ℝ) – known as the n-Hitchin component– to a subset of the set of cross ratios on the boundary at infinity of the group. Similarly, we study some representations into C 1 , h ( 𝕋 ) Diff h ( 𝕋 ) associated to cross ratios and exhibit a “character variety” of these representations. We show that this character variety contains alln-Hitchin components as well as the set of...

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