TY - GEN

T1 - Tractability and Discontinuity

AU - Kaplan, Ronald M.

AU - Wedekind, Jürgen

PY - 2019

Y1 - 2019

N2 - LFG rule systems that embody the explanatory principles of X-bar theory appear to allow for arbitrary repetitions of nodes, particularly complements and coheads, that map to the same f-structure. Such X-bar compliant grammars thus fail to meet the requirements for tractable computation that have been identified in recent work (Wedekind & Kaplan, in press). This raises the question whether those grammars also fail of descriptive accuracy in that they provide for derivations with syntactic dependencies that are not attested in natural languages. We address what may be regarded as a discrepancy between explanatory and descriptive adequacy by imposing finite bounds on the degree of discontinuity of grammatical functions and the number of nodes in functional domains. We introduce additional filtering conditions on derivations, along the lines of Completeness and Coherence and the original nonbranching dominance prohibition, that make it possible to decide that derivations respect those bounds. Grammars that embody the principles of X-bar theory and satisfy these bounds and additional requirements are amenable to tractable processing.

AB - LFG rule systems that embody the explanatory principles of X-bar theory appear to allow for arbitrary repetitions of nodes, particularly complements and coheads, that map to the same f-structure. Such X-bar compliant grammars thus fail to meet the requirements for tractable computation that have been identified in recent work (Wedekind & Kaplan, in press). This raises the question whether those grammars also fail of descriptive accuracy in that they provide for derivations with syntactic dependencies that are not attested in natural languages. We address what may be regarded as a discrepancy between explanatory and descriptive adequacy by imposing finite bounds on the degree of discontinuity of grammatical functions and the number of nodes in functional domains. We introduce additional filtering conditions on derivations, along the lines of Completeness and Coherence and the original nonbranching dominance prohibition, that make it possible to decide that derivations respect those bounds. Grammars that embody the principles of X-bar theory and satisfy these bounds and additional requirements are amenable to tractable processing.

M3 - Conference article

VL - 19

SP - 130

EP - 148

JO - Proceedings of the LFG-conference

JF - Proceedings of the LFG-conference

SN - 1098-6782

Y2 - 8 July 2019 through 10 July 2019

ER -