Abstract
In the paper we examine data dependencies in the algorithm of back substitution in the problem of solving triangular systems of linear equations. The aim of the paper is to illustrate the structural blanks (SB) notation in consistency proof of data dependencies in loop programs. Data dependency semantics of programs is introduced and investigated. The introduced notation constitutes the theoretical basis of data dependencies in SB. Two structural modules – a sequential S-module and a parallel one – are examined.