The fact that GPSG (Gazdar et al. , 1985) makes heavy use of defaults, has led to some research concerning the compatibility of GPSG with a formalism such PATR-II (Shieber 1986a) and concerning the logical nature of the mechanisms used in GPSG (Evans 1987). Gazdar et al. 1985, pp. 1 Whether this kind of situation can occur in GPSG probably depends on whether one is willing to conclude from examples such as: S[COMPo~] ---* {[SUBCATa]}, H[COMP NIL] (Gazdar et al. 1985, p. 248) that covariation of arbitrary categories is in principle not excluded in this formalism. The most common linguistic application for default inheritance is to encode lexical generalizations (e.g. , Boguraev and Pustejovsky 1990; Briscoe, Copestake, and Boguraev 1990; Vossen and Copestake 1993; Daelemans 1987; Evans and Gazdar 1989a, 1989b, 1996; Flickinger, Pollard, and Wasow 1985; Flickinger 1987; Flickinger and Nerbonne 1992; Kilgarriff 1993; Krieger and Nerbonne 1993; Sanfilippo 1993; Shieber 1986a), but defaults have also been used for specification in syntactic theory (e.g. , Gazdar 1987; Shieber 1986b), and for the analysis of gapping constructions (Kaplan 1987) and ellipsis (Grover et al. 1994). Gazdar et al. 1985), and we assume basic familiarity with this type of analysis.