On linear decomposition of Boolean functions

Disjunctive decompositions of Boolean functions taken after a linear substitution on the set of arguments are considered. For any component of such a decomposition, a notion of a substantial variables subspace is introduced. The main topic of the article is to give some sufficient condition under which the both these subspaces unequally determine each other in a simple disjunctive decomposition of a function having the trivial stabiliser group of shifts. The case of iterative disjunctive decomposition is considered too.