Schaefer classes, Post classes and Galois connections

An universal algebra on the set of Boolean functions with operations of function conjunction, projection with respect to a variable and transposition of variables is considered. The structure of functions constituting subalgebras of this algebra are described. It is shown that there exists a Galois connection between subalgebras of the algebra considered and subalgebras of iterative Post algebra; this connection links our results with known papers on Post classes.