Affine Parts of Abelian Surfaces as Complete Intersections of Four Quadrics.
On étudie la relation entre le -rang des variétés abéliennes en caractéristique et la stratification de Kottwitz-Rapoport de la fibre spéciale en de l’espace de module des variétés abéliennes principalement polarisées avec structure de niveau de type Iwahori en . En particulier, on démontre la densité du lieu ordinaire dans cette fibre spéciale.
For an Abelian Variety , the Künneth decomposition of the rational equivalence class of the diagonal gives rise to explicit formulas for the projectors associated to Beauville's decomposition (1) of the Chow ring , in terms of push-forward and pull-back of -multiplication. We obtain a few simplifications of such formulas, see theorem (4) below, and some related results, see proposition (9) below.
We consider a generic complex polynomial in two variables and a basis in the first homology group of a nonsingular level curve. We take an arbitrary tuple of homogeneous polynomial 1-forms of appropriate degrees so that their integrals over the basic cycles form a square matrix (of multivalued analytic functions of the level value). We give an explicit formula for the determinant of this matrix.
Si costruiscono famiglie di curve iperellittiche col —rango della varietà jacobiana uguale a zero. La costruzione sfrutta le proprietà elementari dell’operatore di Cartier e delle estensioni -cicliche dei corpi con la caratteristica maggiore di zero.