Date: 24 May 2005

The Boolean closures of the deterministic and nondeterministic context-free languages

* Final gross prices may vary according to local VAT.

Get Access

Abstract

The Boolean closure of the deterministic context-free languages is properly contained in the intersection-closure of the context-free languages and the latter is properly contained in the Boolean closure of the context-free languages. The class of context-free languages and the Boolean closure of the deterministic context-free languages are incomparable in the sense that neither one is contained in the other. The intersection-closures of the deterministic and nondeterministic context-free languages are not principal AFDL's.

The research in this paper was supported in part by the National Science Foundation under Grant GJ-803.