Leftist Grammars and the Chomsky Hierarchy

13 years 5 months ago
Leftist Grammars and the Chomsky Hierarchy
Leftist grammars can be characterized in terms of rules of the form a → ba and cd → d, without distinction between terminals and nonterminals. They were introduced by Motwani et. al. [9], where the accessibility problem for some general protection system was related to these grammars. This protection system was originally proposed in [3, 10] in the context of Java virtual worlds. Here, the accessibility problem is formulated in the form “Can object p gain (illegal) access to object q by a series of legal moves (as prescribed by the policy)?”. It was shown [9] that the membership problem for leftist grammar is decidable what implied the decidability of the accessibility problem for the appropriate protection system. We study relationships between language classes defined by various types of leftist grammars and classes of the Chomsky hierarchy. We show that general leftist grammars can recognize languages which are not context free, answering in negative the question from [9]. ...
Tomasz Jurdzinski, Krzysztof Lorys
Added 27 Jun 2010
Updated 27 Jun 2010
Type Conference
Year 2005
Where FCT
Authors Tomasz Jurdzinski, Krzysztof Lorys
Comments (0)