Head of the Laboratory of Algebra and logic
Doctor of Physical and Mathematical Sciences, Professor
Main scientific achievements:
Proved (together with Steffen Lempp, USA) existence of a family of dce sets, Rogers semilattice which can be partitioned into a principal ideal and the principal filter generated Fridberg numbering. In particular, such a family has exactly two minimum numbering are Fridberg. It is proved (with S.S.Goncharov, Russia) that any computable family of infinite sets in the arithmetical hierarchy has infinitely many minimal computable numberings. (Note that any finite family has the lowest numbering). In the Ershov hierarchy found a family consisting of a pair of nested sets and having a singleton Rogers semilattice.