Noun compounds have a variety of scope possibilities not available to adjectives, as illustrated by the single bracketing possibility in ((343)) and the two possibilities for ((344)). This ambiguity is manifested in the XTAG grammar by the two possible adjunction sites in the noun-noun compound tree itself. Subsequent modifying nouns can adjoin either onto the Nr node or onto the N anchor node of that tree, which results in exactly the two bracketing possibilities shown in ((344)). This inherent structural ambiguity results in noun-noun compounds regularly having multiple derivations. However, the multiple derivations are not a defect in the grammar because they are necessary to correctly represent the genuine ambiguity of these phrases.
Noun-noun compounds have no restriction on number. XTAG allows nouns to be either singular or plural as in ((345))-((347)).