The Hardness Results of Actively Predicting Simple Subclasses of Context-Free Grammars
نویسندگان
چکیده
In this paper, we present the hardness results of actively predicting context-free grammars that the number of nonterminals is just one, that is sequential, that is properly sequential, and that the number of nonterminals appearing in the righthand side of each production is bounded by some constant. keywords: computational learning theory, prediction, grammatical inference, formal language
منابع مشابه
The Complexity of Learning Principles and Parameters Grammars
We investigate models for learning the class of context-free and context-sensitive languages (CFLs and CSLs). We begin with a brief discussion of some early hardness results which show that unrestricted language learning is impossible, and unrestricted CFL learning is computationally infeasible; we then briefly survey the literature on algorithms for learning restricted subclasses of the CFLs. ...
متن کاملGeneral Perspective on Distributionally Learnable Classes
Several algorithms have been proposed to learn different subclasses of context-free grammars based on the idea generically called distributional learning. Those techniques have been applied to many formalisms richer than context-free grammars like multiple context-free grammars, simple contextfree tree grammars and others. The learning algorithms for those different formalisms are actually quit...
متن کاملSubclasses of Tree Adjoining Grammar for RNA Secondary Structure
Several grammars have been proposed for representing RNA secondary structure including pseudoknots. In this paper, we introduce subclasses of multiple context-free grammars which are weakly equivalent to these grammars for RNA, and clarify the generative power of these grammars as well as closure property.
متن کاملAn Attempt Towards Learning Semantics: Distributional Learning of IO Context-Free Tree Grammars
Solid techniques based on distributional learning have been developed targeting rich subclasses of CFGs and their extensions including linear context-free tree grammars. Along this line we propose a learning algorithm for some subclasses of IO contextfree tree grammars.
متن کاملThe Inclusion Problem for Some Subclasses of Context-Free Languages
− By a reduction to Post’s Correspondence Problem we provide a direct proof of the known fact that the inclusion problem for unambiguous context-free grammars is undecidable. The argument or some straightforward modification also applies to some other subclasses of context-free languages such as linear languages, sequential languages, and DSClanguages (i.e., languages generated by context-free ...
متن کامل