While ((500))-((502)) are all semantically anomalous, ((502)) also suffers
from an ordering problem that makes it seem ungrammatical as well. Since the
XTAG grammar focuses on syntactic constructions, it should accept
((499))-((501)) but not ((502)). Both the auxiliary and determiner
ordering systems are structured on the idea that certain types of lexical items
(specified by features) can adjoin onto some types of lexical items, but not
others. We believe that an analysis of adjectival ordering would follow the
same type of mechanism.