Canonical and filling subgroups of formal groups.
Cartier-Dieudonné theory for Chow groups.
Catégories dérivées et variétés de Deligne-Lusztig
Challenging problems on affine -space
Characteristic varieties of character sheaves.
Characterization of the complex projective space by holomorphic vector fields.
Chern classes of reductive groups and an adjunction formula
In this paper, I construct noncompact analogs of the Chern classes for equivariant vector bundles over complex reductive groups. For the tangent bundle, these Chern classes yield an adjunction formula for the (topological) Euler characteristic of complete intersections in reductive groups. In the case where a complete intersection is a curve, this formula gives an explicit answer for the Euler characteristic and the genus of the curve. I also prove that the higher Chern classes vanish. The first...
Class Groups of Localities of Rings of Invariants of Reductive Algebraic Groups.
Classes d'Euler équivariantes et points rationnellement lisses
Lorsqu’un tore agit sur une variété algébrique complexe munie de la topologie transcendante, nous définissons la classe d’Euler -équivariante d’un point fixe isolé , qu’il soit lisse ou non. Cette classe est une fraction rationnelle à un nombre fini de variables et lorsque est rationnellement lisse dans , c’est un polynôme qui s’identifie canoniquement à la classe d’Euler équivariante usuelle, mais, réciproquement, lorsque la classe d’Euler équivariante est polynomiale, il n’est pas toujours...
Classi coniugate in
Classical Godeaux Surface in Characteristic P.
Classical projective geometry and arithmetic groups.
Classification of group subschemes in , that contain a split maximal torus.
Classification of low-dimensional orbit closures in varieties of quiver representations
We classify the affine varieties of dimension at most 4 which occur as orbit closures with an invariant point in varieties of representations of quivers. Moreover, we show that they are normal and Cohen-Macaulay.
Classification of spherical varieties
We give a short introduction to the problem of classification of spherical varieties, by presenting the Luna conjecture about the classification of wonderful varieties and illustrating some of the related currently known results.
Classification of strict wonderful varieties
In the setting of strict wonderful varieties we prove Luna’s conjecture, saying that wonderful varieties are classified by combinatorial objects, the so-called spherical systems. In particular, we prove that primitive strict wonderful varieties are mostly obtained from symmetric spaces, spherical nilpotent orbits and model spaces. To make the paper as self-contained as possible, we also gather some known results on these families and more generally on wonderful varieties.
Closures of Conjugacy Classes of Matrices are Normal.
Closures of SL(2)-Orbits in Projective Spaces.
Clusters of infinitely near points.
Co-fibered products of algebraic curves
We give examples of failure of the existence of co-fibered products in the category of algebraic curves.