Synchronous Context-Free Grammars (SCFGs), also known as syntax-directed translation schemata [1,2], are unlike context-free grammars in that they do not have a binary normal form. In general, parsing with SCFGs takes space and time polynomial in the length of the input strings, but with the degree of the polynomial depending on the permutations of the SCFG rules. We consider linear parsing strategies, which add one nonterminal at a time. We show that for a given input permutation, the problems of finding the linear parsing strategy with the minimum space and time complexity are both NP-hard. (C) 2015 Elsevier Inc. All rights reserved.
Crescenzi, P., Gildea, D., Marino, A., Rossi, G., Satta, G. (2015). Synchronous context-free grammars and optimal linear parsing strategies. JOURNAL OF COMPUTER AND SYSTEM SCIENCES, 81(7), 1333-1356 [10.1016/j.jcss.2015.04.003].
Synchronous context-free grammars and optimal linear parsing strategies
ROSSI, GIANLUCA;
2015-01-01
Abstract
Synchronous Context-Free Grammars (SCFGs), also known as syntax-directed translation schemata [1,2], are unlike context-free grammars in that they do not have a binary normal form. In general, parsing with SCFGs takes space and time polynomial in the length of the input strings, but with the degree of the polynomial depending on the permutations of the SCFG rules. We consider linear parsing strategies, which add one nonterminal at a time. We show that for a given input permutation, the problems of finding the linear parsing strategy with the minimum space and time complexity are both NP-hard. (C) 2015 Elsevier Inc. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
