Maps between local Picard groups

We study the local Picard group of singularities. We study those elements in the local Picard group that become trivial either when pulled-back to the normalization or when restricted to a hyperplane section. In the second case we improve the similar results of SGA2. Version2: Many small changes, new Theorem 4 added

Local units versus local projectivity. Dualisations: Corings with local structure maps

We unify and generalize different notions of local units and local projectivity. We investigate the connection between these properties by constructing elementary algebras from locally projective modules. Dual versions of these constructions are discussed, leading to corings with local comultiplications, corings with local counits and rings with local multiplications.Comment: 22 pages, including a correction to Proposition 1.

A New Method of Extension of Local Maps of Banach Spaces. Applications and Examples

A known classical method of extension of smooth local maps of Banach spaces uses smooth bump functions. However, such functions are absent in the majority of infinite-dimensional Banach spaces. This is an obstacle in the development of local analysis, in particular in the questions of extending local maps onto the whole space. We suggest an approach that substitutes bump functions with special maps, which we call blid maps. It allows us to extend smooth local maps from non-smooth spaces, such as $C^q[0,1], q=0,1,...$. As an example of applications, we show how to reconstruct a map from its derivatives at a point, for spaces possessing blid maps. We also show how blid maps can assist in finding global solutions to cohomological equations having linear transformation of argument.Comment: arXiv admin note: substantial text overlap with arXiv:1703.0629