The paper considers certain extensions of the system LC introduced in Dunn & Meyer 1997. LC is a structurally free system , but it has combinators as formulas in the place of structural rules. We consider two ways to extend LC with conjunction and disjunction depending on whether they distribute over each other or not. We prove the elimination theorem for the systems. At the end of the paper we give a Routley-Meyer style semantics for the distributive extension, including some (...) new definitions and an algorithm which are used in proving a representation theorem in general, i.e., for arbitrary combinators. (shrink)

Structurally free logic LC was introduced in [4]. A natural extension of LC, in particular, in a sequent formulation, is by conjunction and disjunction that do not distribute over each other. We define a set theoretical semantics for these logics via constructing a representation of a lattice that we extend by intensional operations. Canonically, minimally overlapping filter-ideal pairs are used; this construction avoids the use of an equivalent of the axiom of choice and lends transparency to the structure. We also (...) discuss adapting the present semantics for substructural logics, as well as, the question of cannnonicity of LC+. (shrink)