The phenomenon of state reduction

Abstract: A theory of quantum measurement was introduced some time ago that was based on the notion of the so-called separation status. This separation status had a spatial, local character, so that the theory worked only in special cases. Nevertheless, it enabled a description of state reduction process that was specific in where, when and under which objective conditions the process occurs and that preserved the unitary transformation symmetry of quantum mechanics. Now, in an accompanying paper (arxiv:1411.5524), a completely general mathematical definition of the status is given and analyzed. The present paper reformulates the theory of state reduction accordingly. A general mathematical form of the process is postulated and illustrated by examples of Stern-Gerlach experiment and of screening.