On free annotated algebras Original Research Article

In Lewin et al. (Studia Logica 59(3) (1997) 359–386) the authors proved that certain systems of annotated logics are algebraizable in the sense of Block and Rigozzi (Memoirs AMS 77 (1989) 396). Later in Lewin et al. (Proceedings of the X SLALM, Bagota, 1995, Marcel Dekker, New York, 1998, pp. 279–293; Proceedings of the WAAL, Barcelona, 1997, submitted for publication) the study of the associated quasi-varieties of annotated algebras is initiated. In this paper we continue the study of the these classes of algebras, in particular, we report some recent results about the free annotated algebras.