  Probably building non procedural languages is the most prospective way for
parallel programming just because non procedural means no fixed way for
execution. The article consists of 3 parts. In first part we consider formal
systems for definition a named datasets and studying an expression power of
different subclasses. In the second part we consider a complexity of algorithms
of building sets by the definitions. In third part we consider a fullness and
flexibility of the class of program based data set definitions.
