We show that a set of three axioms, together with modus ponens, suffices to build up a formal system for the class R of all quadruples (L,6,T,J), in which (L,6) is a partially ordered set with a top element, and T is a triangular norm on (L,6) that has a residuated implication J. We show that this R is not a variety. 2004 Elsevier Inc. All rights reserved.