On pure, terminal invariant and nonterminal invariant interpretations of EOL forms

AbstractThis paper (re) considers some basic axioms of the theory of EOL forms. Two new kinds of interpretations are introduced; they form natural steps in-between ordinary and pure interpretations. Various properties of those interpretations are proved and several open problem concerning pure interpretations are solved. In particular certain results are proved which show that synchronized EOL forms have a natural place in the theory of EOL forms (independently of their role as the normal form for EOL systems on language level)