tailieunhanh - Báo cáo khoa học: "Parsing Parallel Grammatical Representations"

Traditional accounts of quantifier scope employ qualitative constraints or rules to account for scoping preferences. This paper outlines a feature-based parsing algorithm for a grammar with multiple simultaneous levels of representation, one of which corresponds to a partial ordering among quantifiers according to scope. The optimal such ordering (as well as the ranking of other orderings) is determined in this grammar not by absolute constraints, but by stochastic heuristics based on the degree of alignment among the representational levels. . | Parsing Parallel Grammatical Representations Derrick Higgins Department of Linguistics University of Chicago 1050 East 59th Street Chicago IL 60626 dchiggin@ Abstract Traditional accounts of quantifier scope employ qualitative constraints or rules to account for scoping preferences. This paper outlines a feature-based parsing algorithm for a grammar with multiple simultaneous levels of representation one of which corresponds to a partial ordering among quantifiers according to scope. The optimal such ordering as well as the ranking of other orderings is determined in this grammar not by absolute constraints but by stochastic heuristics based on the degree of alignment among the representational levels. A Prolog implementation is described and its accuracy is compared with that of other accounts. 1 Introduction It has long been recognized that the possibility and preference rankings of scope readings depend to a great degree on the position of scopetaking elements in the surface string Chomsky 1975 Hobbs and Shieber 1987 . Yet most traditional accounts of semantic scopal phenomena in natural language have not directly tied these two factors together. Instead they allow only certain derivations to link the surface structure of a sentence with the representational level at which scope relations are determined place constraints upon the semantic feature-passing mechanism or otherwise emulate a constraint which requires some degree of congruence between the surface syntax of a sentence and its preferred scope reading s . A simpler and more direct approach is suggested by constraint-based multistratal theories of grammar Grimshaw 1997 Jackendoff 1997 Sadock 1991 Van Valin 1993 . In these models it is possible to posit multiple representational levels for a sentence without according ontological primacy to any one of them as in all varieties of transformational grammar. This allows constraints to be formulated which place limits on structural .