crossover (adj.)

A term used in GENERATIVE GRAMMAR, referring to a principle restricting the operation of certain TRANSFORMATIONS which move a NOUN PHRASE (as in PASSIVES, REFLEXIVES, TOUGH MOVEMENT). In an early formulation, the principle states that a transformation cannot apply to a PHRASE-MARKER if it would result in one noun phrase crossing another with which it is CO-REFERENTIAL. The crossover constraint or principle would be used, for example, to explain why passivization cannot apply to structures of the type John washed himself: given an UNDERLYING STRUCTURE John_i washed John_i , to derive a passive John_i was washed by John_i would involve a violation of this principle. In later formulations, more specific CONSTRAINTS on the application of this principle are introduced. In GOVERNMENT-BINDING THEORY, weak crossover refers to cases of crossover phenomena which involve the MOVEMENT of an R-EXPRESSION across a non-C-COMMANDING CO-INDEXED PRONOUN, as in *Who_i does his_i mother love t_i ? Strong crossover refers to cases which involve this movement across a c-commanding co-indexed pronoun, as in [*Whose_i mother]_j does he_i love t_j ? The latter case is eliminated through condition C of binding theory. A LEFTNESS PRINCIPLE excludes all cases of weak crossover, and allows a unified account of these phenomena at the level of LOGICAL FORM.