Pushdown Stores and Subscripts

19 1965 International Conference on Computational Linguistics PUSHDOWN STORES AND SUBSCRIPTS Jacob Mey Lingvistisk Institutt Universitetet i 0slo PoBo 1012, Blindern, Oslo 3, Norway. t-~,,%% \ ,,,.o.,tt<><~/ ' -_Si" Mey 2 PUSHDOWN STORES AND SUBSCRIPTS Abstract Va~rious devices for the imp rovement of phrase structure grammars (PSG) have been suggested recently. In particular, the PSG model with a pushdown store (PSG/PDS) a s described by VoYngve, and the PSG with subscripts (PSG/S) as described by G oHarman are considered. It is contended that such devices, even if they may do away with some of the difficul_ ties of PSG, do not contain sufficient gene_ rative power to produce the structurally corn_ plicated sentences that are generated by other gramma rs (e.g., of transformational type). The handling of multiple disco,Ltinuous con_ stituents (DC) in PSG/PDS, as well as the use of :leletion rules in PSC./S is examined and criticized. It is shown that the improvements on PSG will not allow the grammar to generate a ii the sentences of the language that a trans_ formational grammar (TG) does; moreovdr, the improvements on PSG a re obtained only at the cost of introducing too much power at the PS level, so that the improved gr;~mmars in some cases will exceed the requirem@nts of the de_ scription, i.e. generate non_grammatical sent_ ences. Mey 3 O. Introduction NoChomsky has argued that a PSG is not suff_ icient to generate all the grammatical sent_ ences of a language (Chomsky 1957:3~ ff.). Recently, this conceotion of PSG has been criticized as being too primitive (Yngve 1960:445a, Harman 1963:604 fro), and several ways of improving such a grammar have been suggested: a PDS has been connected with a PSG (Yngve 1960, 1961, 1962); the use of subscript notation has been recommended to give PSG a fair chance in competition with TG (Harman 1963). i. PSG/PDS l.lo PSG and DC The problem of the so_called discontinuous sonstituents (for a detailed treatment, see Wells 1947:96 ff.) has always been a crux in IC analysis. One of the drawbacks of PSG as described by Chomsky, is that it is not able to handle these constituents in a way that satisfies both the formal criteria of the grammar and the intuitive feeling that call and up in, e.g., I called him u~, belong to_ gether and should be treated accordingly in the analysis. Chomsky, in his discussion of PSG limitations, admits the possibility of "extending the notions of phrase structure to account for discontinuities" (Chomsky Mey 4 1957:41), but, he adds, "...fairly serious difficulties arise in any systematic attempt to pursue this course." An attempt in this direction is described by V.Yngve in several articles (see especially Yngve 1960); a lthough the presence of DC is the most annoying of the complications under the PSG model (Yngve 1960:448a), the solution ~ffered to this particular problem implies a wider claim, namely, that "any shortcomings /of PSG, JM/ can be overcome" (Ib.:445a). Accordingly, I will discuss be_ low not only the problem of …

Content truncated to 500 words