A Linear Time Algorithm for Deciding Subject Security
Journal of the ACM (JACM)
On the decidability of accessibility problems (extended abstract)
STOC '00 Proceedings of the thirty-second annual ACM symposium on Theory of computing
Protection in operating systems
Communications of the ACM
Introduction to Automata Theory, Languages and Computability
Introduction to Automata Theory, Languages and Computability
Introduction to Formal Language Theory
Introduction to Formal Language Theory
SP '92 Proceedings of the 1992 IEEE Symposium on Security and Privacy
On Safety in Discretionary Access Control
SP '05 Proceedings of the 2005 IEEE Symposium on Security and Privacy
Leftist Grammars and the Chomsky Hierarchy
Theory of Computing Systems
Leftist Grammars Are Non-primitive Recursive
ICALP '08 Proceedings of the 35th international colloquium on Automata, Languages and Programming, Part II
Toward a compositional theory of leftist grammars and transformations
FOSSACS'10 Proceedings of the 13th international conference on Foundations of Software Science and Computational Structures
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Leftist grammars were introduced by Motwani et al., who established the relationship between the complexity of the accessibility problem (or safety problem) for certain general protection systems and the membership problem for these grammars. The membership problem for leftist grammars is decidable. This implies the decidability of the accessibility problem. It is shown that the membership problem for leftist grammars is PSPACE-hard. Therefore, the accessibility problem in the appropriate protection systems is PSPACE-hard as well. Furthermore, the PSPACE-hardness result is adapted to a very restricted class of leftist grammars, if the grammar is a part of the input.