deletion (n.)

A basic operation within the framework of TRANSFORMATIONAL GRAMMAR, which eliminates a CONSTITUENT of an input PHRASE-MARKER. In classical TG, it accounted for IMPERATIVE SENTENCES, for example (where the SUBJECT and AUXILIARY VERB of an UNDERLYING sentence are deleted, as in kick the ball from You will kick the ball). Other applications of the notion can be found in the transformational treatment of DUMMY symbols, and in several specific transformational operations (e.g. EQUI NP DELETION). Several formal CONSTRAINTS on the use of deletion transformations have been suggested, especially that the deleted elements must be RECOVERABLE, i.e. the deletion transformation must specify the elements to be deleted, and in the output phrase-marker the effects of the deletion must be clearly indicated. If this were not the case, there would be several unfortunate consequences; e.g. a single surface structure could be related to an indefinite number of deep structures, as in He’s been hit, derivable from Someone/John/A bullet . . . hit him.