“…The type-theoretic and logic programming approaches were later combined in the Elf language (Pfenning, 1991). At this point, there was a pause in the development of new frameworks, while the potential and limitations of existing systems were explored in numerous experiments (see Pfenning (1996)). The mid-nineties saw renewed activity with implementations of frameworks based on inductive definitions such as FS 0 (Feferman, 1988;Basin and Matthews, 1996) and ALF (Altenkirch et al, 1994), partial inductive definitions (Eriksson, 1994), substructural frameworks (Miller, 1994;Cervesato and Pfenning, 1996), rewriting logic (Martì-Oliet and Meseguer, 1993), and labelled deductive systems (Gabbay, 1994).…”