On the group of separable quadratic algebras and stacks

Abstract

The aim of this paper is to study the group of isomorphism classes of torsors of finite flat group schemes of rank 2 over a commutative ring $R$. This, in particular, generalises the group of quadratic algebras (free or projective), which is especially well studied. Our approach however, yields new results even in this case.

References in corpus (1)

• Introduction to the language of stacks and gerbes