  The first relevant logics were presented proof theoretically, in terms of axioms and closure under rules. The need for a model theoretic interpretation (given in a classical metatheory) resulted in Sylvan’s co-development with Plumwood of ternary relation semantics for first degree entailment relevant logics (Routley and Routley 1972) and the ensuing Routley-Meyer partnership that proved and extended a range of results for relevant logics (cf. Routley, Meyer, et al. 1982; and Brady 2003). (Cf. Fine 1974; Urquhart 1972.) A Routley-Meyer frame \(\langle W, N, 0, R, {}^* \rangle\) consists of: