2 papers
math.AG2010
Extensions and biextensions of locally constant group schemes, tori and abelian schemes
Cristiana Bertolin
Let S be a scheme. We compute explicitly the group of homomorphisms, the S-sheaf of homomorphisms, the group of extensions, and the S-sheaf of extensions involving locally constant…
math.AG2010
Extensions of Picard stacks and their homological interpretation
Cristiana Bertolin
Let S be a site. We introduce the notion of extensions of strictly commutative Picard S-stacks. We define the pull-back, the push-down, and the sum of such extensions and we comput…