A quasicoherent sheaf of modules (often just “quasicoherent sheaf”, for short) is a sheaf of modules over the structure sheaf of a ringed space that is locally presentable in that it is locally the cokernel of a morphism of free modules. For comparison, by the Serre-Swan theorem a vector bundle on a suitable ringed space is equivalently encoded in its sheaf of sections which is even locally free and projective. In this sense quasicoherent sheaves of modules are a generalization of vector...