Where does the gap in gapping — e.g. Some had ordered mussels, and others swordfish — come from? The traditional answer is deletion (Ross 1970, Hankamer 1979, among others). Johnson (2009) presents a formidable challenge to this view. He argues that gapping cannot arise through deletion because gapping has several unique properties that distinguish it from more familiar deletion operations, such as VP-ellipsis. Instead, Johnson proposes that the gap in gapping arises through ‘low coordination’ — coordination of vPs — and across-the-board movement.

First, I argue that across-the-board movement cannot be a general account of gapping, since it is not able to derive the gap in coordination structures with corrective but (Vicente 2010, Toosarvandani, to appear). Then, I revive a version of the deletion account,  in which gapping is VP-ellipsis in a low-coordination structure. This correctly generates gapping in corrective but sentences. Moreover, once the information-structural properties of low coordinations are taken into consideration — low coordinates must have parallel focus structures — it also accounts for the unique properties of gapping.

References

Ross, John Robert. 1970. Gapping and the order of constituents. In Progress in linguistics, eds. Manfred Bierwisch and Karl Erich Heidolph, 249-259. The Hague: Mouton de Gruyter.
Hankamer, Jorge. 1979. Deletion in coordinate structures. New York: Garland Publishing.
Johnson, Kyle. 2009. Gapping is not (VP-)ellipsis. Linguistic Inquiry 40:289-328.
Toosarvandani, Maziar. To appear. Corrective but coordinates clauses not always but sometimes. Natural Language and Linguistic Theory.
Vicente, Luis. 2010. On the syntax of adversative coordination. Natural Language and Linguistic Theory 28:381-415.