Gapping

Gapping is a form of syntactic ellipsis that occurs in coordinate clauses. It involves the omission of a shared verb phrase in the second conjunct. The result is that the second clause appears to have less verbal content than the first, while still being understood in parallel with it. A classic English example is: John bought several books, and Mary several magazines.

In some cases the second conjunct contains a pro-verb instead of the elided verb: John bought several books, and Mary did too. This do-support variant shows that the second clause relies on an auxiliary to stand in for the omitted verb phrase.

Constraints and variation: Gapping requires a degree of parallel structure between the conjuncts; the material that remains in the second conjunct must align with the corresponding material in the first. The verb phrase that is elided is typically shared, though some displacements or differences are possible when they do not disrupt the overall parallel interpretation. The phenomenon is most transparent when the first clause contains a simple transitive VP.

Cross-linguistic patterns: Gapping is best known from English, but related ellipsis in coordinated clauses appears in other languages as well, with varying permissiveness and realizations. Some languages strongly restrict the form of the second conjunct, while others allow broader omission under parallelism.

Analyses: In generative syntax, gapping is treated as a case of VP-ellipsis or ellipsis under identity. Theoretical accounts differ on whether deletion occurs at the phonological form (PF) under parallel structure, or whether a concealed representation is posited at a deeper level (LF). Gapping is a standard diagnostic for theories of coordination, ellipsis, and syntactic parallelism.