Purities and model theory for sheaves of modules

Professor Mike Prest, University of Manchester. Part of the Logic Seminar Series.

For modules over a ring, there is a notion of pure embedding -- a positive version of elementary embedding -- which is a key concept in the model theory of modules. This extends to sheaves of modules over a ringed space, in particular to sheaves of modules over a scheme. But there is another, geometric, notion of purity. I will say something about the relation between these purities, both for arbitrary sheaves of modules and for quasicoherent sheaves.

This is joint work with Alexander Slavik (Purity in categories of sheaves, arXiv:1809.08981).