Harmonic diffeomorphisms and Teichmüller theory.
Harmonic Maps of the Moduli Space of Compact Riemann Surfaces.
Holomorphic Families of Open Riemann Surfaces.
Holomorphic Maps of Compact Riemann Surfaces Into 2-Dimensional Compact C-Hyperbolic Manifolds.
Homology of origamis with symmetries
Given an origami (square-tiled surface) with automorphism group , we compute the decomposition of the first homology group of into isotypic -submodules. Through the action of the affine group of on the homology group, we deduce some consequences for the multiplicities of the Lyapunov exponents of the Kontsevich-Zorich cocycle. We also construct and study several families of interesting origamis illustrating our results.
Hyperbolic spaces in Teichmüller spaces
We prove, for any , that there is a closed connected orientable surface so that the hyperbolic space almost-isometrically embeds into the Teichmüller space of , with quasi-convex image lying in the thick part. As a consequence, quasi-isometrically embeds in the curve complex of .
Invariants of translation surfaces
We definite invariants of translation surfaces which refine Veech groups. These aid in exact determination of Veech groups. We give examples where two surfaces of isomorphic Veech group cannot even share a common tree of balanced affine coverings. We also show that there exist translation surfaces of isomorphic Veech groups which cannot affinely cover any common surface. We also extend a result of Gutkin and Judge and thereby give the first examples of noncompact Fuchsian...
Isometries of the Teichmüller metric
Iteration on Teichmüller space.
Kleinian groups, the Teichmueller space and Mostow's rigidity theorem.
Komplexe Unterstrukturen mit endlichen Trägern.
Le spectre des longueurs des surfaces hyperboliques : un exemple de rigidité.
Après avoir présenté quelques résultats récents portant sur l’étude du spectre des longueurs des surfaces hyperboliques avec ou sans singularités, on démontre que les sphères possédant trois points coniques sont, dans leur classe, spectralement rigides.
Les groupes de triangles sont déterminés par leur spectre des longueurs
On décrit le début du spectre des longueurs des groupes de triangles ayant un angle droit et on montre que le spectre des longueurs caractérise la classe d’isométrie d’un tel groupe.
Limit points of lines of minima in Thurston's boundary of Teichmüller space.
Local and global theory of the moduli of polarized Calabi-Yau manifolds.
In this paper we review the moduli theory of polarized CY manifolds. We briefly sketched Kodaira-Spencer-Kuranishi local deformation theory developed by the author and G. Tian. We also construct the Teichmüller space of polarized CY manifolds following the ideas of I. R. Shafarevich and I. I. Piatetski-Shapiro. We review the fundamental result of E. Viehweg about the existence of the course moduli space of polarized CY manifolds as a quasi-projective variety. Recently S. Donaldson computed the moment...
Matrices for Fenchel-Nielsen coordinates.
Modules des surfaces de Riemann
Moduli spaces of abelian differentials : the principal boundary, counting problems, and the Siegel-Veech constants
A holomorphic 1-form on a compact Riemann surface S naturally defines a flat metric on S with cone-type singularities. We present the following surprising phenomenon: having found a geodesic segment (saddle connection) joining a pair of conical points one can find with a nonzero probability another saddle connection on S having the same direction and the same length as the initial one. A similar phenomenon is valid for the families of parallel closed geodesics. We give a complete description of...
Moduli spaces of local systems and higher Teichmüller theory
Let G be a split semisimple algebraic group over Q with trivial center. Let S be a compact oriented surface, with or without boundary. We define positive representations of the fundamental group of S to G(R), construct explicitly all positive representations, and prove that they are faithful, discrete, and positive hyperbolic; the moduli space of positive representations is a topologically trivial open domain in the space of all representations. When S have holes, we defined two moduli spaces closely...
Moduli spaces of stable real algebraic curves