ParisDefeasibleConstraints

LKB defeasible constraints:

same-local-by-default-lex-rule := lex-rule &
  [ SYNSEM.LOCAL [ CAT /l #cat,
                   AGR /l #cont,
                   CTXT /l #ctxt ],
    C-CONT.HOOK /l #hook,
    DTR.SYNSEM.LOCAL [ CAT /l #cat,
                       CONT.HOOK /l #hook,
                       AGR /l #agr,
                       CTXT /l #ctxt ]].

acc-to-dat-lex-rule := same-local-by-default-lex-rule &
  [ SYNSEM.LOCAL.CAT.VAL.COMPS.FIRST.LOCAL.CAT.HEAD.CASE dat,
    DTR.SYNSEM.LOCAL.CAT.VAL.COMPS.FIRST.LOCAL.CAT.HEAD.CASE acc ].

Result has mother's SYNSEM.LOCAL.CAT unconstrained except for FIRST..CASE.

Intended result was for the defeasible constraints to be pushed down (as in Sag, Wasow & Bender 2003):

[ SYNSEM.LOCAL [ CAT [ HEAD /l #head,
                       VAL [ SUBJ /l #subj,
                             COMPS [ FIRST [ NON-LOCAL /l #non-loc,
                                             ... ],
                                     REST /l #rest ]]],
                 AGR /l,
                 ... ],
  DTR.SYNSEM.LOCAL [ CAT [ HEAD /l #head,
                           VAL [ SUBJ /l #subj,
                                 COMPS [ FIRST [ NON-LOCAL /l #non-loc,
                                             ... ],
                                         REST /l #rest ]]],
                 AGR /l,
                 ... ].

This would allow us to define lexical rule types that copy up whatever isn't changed, even without knowing what features a customization system user might decide to add, either in the customization system or later.