On an extension of the class on context-free languages

Journal Article · Wed Nov 01 04:00:00 EST 1995 · Programming and Computer Software

OSTI ID:274216

Dubasova, O A; Mel`nikov, B F ^[1]

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1. Moscow State Univ. (Russian Federation)

The global supermonoids of free monoids with an infinite number if generators are considered. Special equality problems for supermonoids are investigated. The criteria of the equalities considered in supermonoids are applied to the study of the equivalence of two languages of the following form: [u{sub 1}...u{sub n}ZV{sub n}...V{sub 1}{vert_bar} n{equivalent_to} 0, z {element_of} L, (u{sub i}, v{sub i}){element_of} {mu}], where the languages are considered over a infinite alphabet {Re}, L {improper_subset} {Re}*, {mu} {improper_subset} {Re}* x {Re}*, and the sets L and {mu} may be infinite in the paper. Each languages can be regarded of as an {open_quotes}infinite{close_quotes} extension of the context-free (CF) language specified by the grammar with the following set of production: [S {yields} z {vert_bar} z {Re} L] {union} [S {yields} uSv {vert_bar} (u, v){Re} {mu}]. The necessary and sufficient conditions of equivalence of these languages are proved under certain restrictions formulated in the paper. These criteria can be applied to the equivalence problem in subclasses of the CF-language class. A few examples of grammatical constructions specifying the languages that satisfy these restrictions are given.

• OSTI ID: 274216
• Journal Information: Programming and Computer Software, Journal Name: Programming and Computer Software Journal Issue: 6 Vol. 21; ISSN PCSODA; ISSN 0361-7688
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
DESIGN
MATHEMATICAL LOGIC
PROGRAMMING LANGUAGES