### Abstract

Coarse-grining is a basic concept in mathematical statistics and its analogue may be defined in the formalism of quantum mechanics. In the lecture sufficiency of a coarse-graining is discussed with respect to a family of states. Charaterizations of sufficiency are given. The equality case for the strong subadditivity of the von Neumann entropy and the Koashi-Imoto theorem are among the applications. The lecture is partially based on joint work with Anna Jencova.

### Related Links

- http://www.math.bme.hu/~petz - homepage of the speaker