Class numbers of pairs of symmetric matrices
Class numbers of positive definite quaternary quadratic forms.
Classes de Stiefel-Whitney de Formes quadratiques et de représentations galoisiennes réelles.
Classes de Stiefel-Whitney en cohomologie étale
Classification of hermitian forms and semisimple gorups over fields of virtual cohomological dimension one.
Classification of two genera of 32-dimensional lattices of rank 8 over the Hurwitz order.
Classification Theorems for Quadratic Forms over Fields
Clifford algebras, Möbius transformations, Vahlen matrices, and -loops
In this paper we show that well-known relationships connecting the Clifford algebra on negative euclidean space, Vahlen matrices, and Möbius transformations extend to connections with the Möbius loop or gyrogroup on the open unit ball in -dimensional euclidean space . One notable achievement is a compact, convenient formula for the Möbius loop operation , where the operations on the right are those arising from the Clifford algebra (a formula comparable to for the Möbius loop multiplication...
Clifford k-algebras and k*-groups.
CM liftings of supersingular elliptic curves
Assuming GRH, we present an algorithm which inputs a prime and outputs the set of fundamental discriminants such that the reduction map modulo a prime above from elliptic curves with CM by to supersingular elliptic curves in characteristic is surjective. In the algorithm we first determine an explicit constant so that implies that the map is necessarily surjective and then we compute explicitly the cases .
Codes et formes quadratiques
Co-fibered products of algebraic curves
We give examples of failure of the existence of co-fibered products in the category of algebraic curves.
Cohomologie galoisienne : progrès et problèmes
Complexes de groupes de type multiplicatif et groupe de Brauer non ramifié des espaces homogènes
On calcule par des méthodes arithmétiques le groupe de Brauer non ramifié des espaces homogènes de groupes algébriques linéaires sur différents corps. Les formules obtenues font intervenir l’hypercohomologie de complexes de groupes de type multiplicatif.
Composition of binary quadratic forms
Composition of binary quadratic forms over integral domains
Composition of norm-type forms.
Composition of quaternary quadratic forms
Compositions of quadratic forms with quadratic, bilinear or Hermitian forms.
Computations of cyclotomic lattices.