In early analyses of nominal ellipsis in generative syntax, ellipsis was analyzed as null anaphora, where missing material is interpreted under identity with an antecedent in much the same way as a lexical pronoun. Ellipsis was analyzed either as the result of a deletion transformation, in which ellipsis results from deletion of a lexical pro-form, one, or as a base-generated empty category subject to rules of interpretation. Within the Principles and Parameters framework, nominal ellipsis was subsequently analyzed as involving proper government of pro, an empty pronominal category, which has to be licensed and identified. This approach led to in-depth, cross-linguistic analyses of the properties of the determiner and quantifier systems to determine the feature specifications of different functional heads, and the role those features play in licensing and identification. This research also explored connections between ellipsis in DP and substantive adjective and partitive constructions, in particular partitives which involve clitic en (French) and ne (Italian). In current research the same questions are still debated, but in more recent theoretical frameworks: the Minimalist Program, Distributed Morphology and Cartography. The questions concern PF-deletion or late insertion, the role of functional projections such as Classifier Phrase and nP, and the role of focus.