In "Edge-Based Clausal Syntax", Paul Postal rejects the notion that an
English phrase of the form [V + DP] invariably involves a grammatical
relation properly characterized as a direct object. He argues instead that
at least three distinct relations occur in such a structure. The different
syntactic properties of these three kinds of objects are shown by how they
behave in passives, middles, -able forms, tough movement, wh-movement,
Heavy NP Shift, Ride Node Raising, re-prefixation, and many other tests.
This proposal renders Postal’s position sharply different from that of
Chomsky, who defined a direct object structurally as [NP, VP], and with the
traditional linguistics text’s definition of the direct object as the DP
sister of V.
According to Postal’s framework, sentence structures are complex graph
structures built on nodes (vertices) and edges (arcs). The node that heads
a particular edge represents a constituent that bears the grammatical
relation named by the edge label to its tail node. This approach allows two
DPs that have very different grammatical properties to occupy what looks
like identical structural positions.
The contrasting behaviors of direct objects, which at first seem
anomalous--even grammatically chaotic--emerge in Postal’s account as
nonanomalous, as symptoms of hitherto ungrasped structural regularity.