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Inductive Inference of Monogenic Pure ContextFree Languages^{**}
Noriyuki TANIDA Takashi YOKOMORI
Publication
IEICE TRANSACTIONS on Information and Systems
Vol.E79D
No.11
pp.15031510 Publication Date: 1996/11/25
Online ISSN:
DOI:
Print ISSN: 09168532 Type of Manuscript: PAPER Category: Algorithm and Computational Complexity Keyword: inductive inference, monogenic pure contextfree languages, polynomialtime,
Full Text: PDF(658KB)>>
Summary:
A subclass of contextfree languages, called pure contextfree languages, which is generated by contextfree grammar with only one type of symbol (i.e., terminals and nonterminals are not distinguished), is introduced and the problem of identifying from positive data a restricted class of monogenic pure contextfree languages (monoPCF languages, in short) is investigated. The class of monoPCF languages is incomparable to the class of regular languages. In this paper we show that the class of monoPCF languages is polynomial time identifiable from positive data. That is, there is an algorithm that, given a monoPCF language L, identifies from positive data, a grammar generating L, called a monogenic pure contextfree grammar (monoPCF grammar, in short) satisfying the property that the time for updating a conjecture is bounded by O(N^{3}), where N is the sum of lengths of all positive data provided. This is in contrast with another result in this paper that the class of PCF languages is not identifiable in the limit from positive data.

