Under this heading fall a number of phenomena that can be collectively referred to as discontinuity and trace phenomena, i.e. movement phenomena where an element has been moved (or removed) from its `logical' position. In 63 is an example in which a relative clause has been moved from its logical position in an NP:
(63) | A man was at the door who wanted to speak to you |
(64) | [NP A man [*1] NP] [VP was [at the door] VP] [CL-Rel*1 who wanted to speak to you CL-Rel] |
(65) | [S [NP Who NP*1] [Aux does Aux] [NP she NP] [VP work [PP for [*1] PP] VP] ? S] |
(66) | [S [NP He NP] [VP has [NP nothing [VP to live [PP for [*0] PP] VP] NP] VP] . S] |
Indices can also be used to indicate `underlying' Subject or Object postions in the complement of so-called raising constructions and with control verbs. In 67 James is the Subject of tried but logically, it is also the Subject of to go:
(67) | [NP James NP*1] [VP tried [ [CL [*1] to go CL] VP] |
(68) | [NP Mary NP] [VP believed [NP John NP*1] [CL [*1] to be at home CL] VP] |
Languages differ in the range of possibilities of discontinuity, raising constructions and control phenomena (e.g. in Raising-to-Object constructions, the Dutch equivalent of believe can only take tensed complements, not infinitival ones as in English). However, each language will probably have a number of constructions in which logical relations need to be indicated using an index system. It is beyond the scope of this report to go into further detail, but the ideas set forth here should enable a simple indexing system to be implemented. Details of two actual applications of such systems can be found in the documentation of the SUSANNE corpus (Sampson 1995, Ch. 5) and the Penn Treebank (Marcus et al. 1994).