Abstract

The paper was read at the Autumn School of Logic organized by the Section of Logic, Institute of Philosophy and Sociology, Polish Academy of Sciences, in Ustronie, September 4-12, 1979. In this paper two problems are considered. The rst one concerns existence of matrices strongly adequate for certain logics and is connected with some results presented in [6]. All matrices constructed here have the same form, more precisely, they are products of Lindenbaum's matrices. The second problem concerns Maksimova's principle of separating variables