N-bar deletion

N-bar deletion is a phenomenon of an NP without an overt head but with either a numeral specifier (i) or a possessive pronoun (ii).

(i) John has [NP three [N' e]] (ii) These books must be [NP hers [N' e]]

If the N' is an empty category, as indicated in (i) and (ii), it poses a problem for the formulation of the ECP, which it appears to violate. Alternatively, these NPs may in fact be DPs without NP complement.

Links
Utrecht Lexicon of Linguistics