Showing papers on "Chomsky hierarchy published in 1973"

Extension of tabled 0L-systems and languages

Abstract: This paper introduces a new family of languages which originated from a study of some mathematical models for the development of biological organisms. Various properties of this family are established and in particular it is proved that it forms a full abstract family of languages. It is compared with some other families of languages which have already been studied and which either originated from the study of models for biological development or belong to the now standard Chomsky hierarchy. A characterization theorem for context-free languages is also established.

On the Formal Definition of Assembly Languages.

Abstract: A method for forming a negative image comprising imagewise exposing a photographic material to provide exposed areas and unexposed areas, said material comprising, on a support, (1) an emulsion layer containing a light-sensitive silver halide, (2) unsensitized silver halide metallic salt grains which are more soluble in a developer than the light sensitive silver halide, and (3) nuclei for physical development, processing said material in the presence of a reducing agent and a solvent for said grains with said developer containing a substance which renders said grains less soluble by adsorbing thereto, said developer rendering said grains in said exposed areas and not in said unexposed areas soluble in said solvent, whereby metal ions are released and deposited on said nuclei.

Constructions of Grammars for Formal Languages.

Abstract: The present invention relates to novel 1-azaxanthone-3-carboxylic acid and its derivatives usable for effective medicines for the treatment of allergic diseases, which are shown by the following formula (I) (I) wherein R1 is hydrogen, alkyl, phenyl, carboxyl, hydroxyl, alkoxy or amino group which may be unsubstituted or substituted by one alkyl, m is 0, 1 or 2 and R2 is alkyl, alkoxy, halogen, nitro, hydroxy, carboxyl, butadienylene (-CH=CH-CH=CH-) which forms a benzene ring with any adjacent carbon atoms or amino group which may be unsubstituted or substituted by at least one alkyl, and their physiologically acceptable salts.

Formal metalanguage and formal theory as two aspects of generative grammar

Abstract: As is known, metalanguage is a language by means of which another language is described. The latter is called object-language. One and the same language may play the role of object-language and metalanguage. For example, the Russian language taken as an object of linguistic description is an object-language, the Russian language used for a linguistic description of Russian is a metalanguage. There are non-formal and formal metalanguages. For example, the Russian language used in ordinary grammars of Russian as a means of describing the Russian language is a non-formal metalanguage. Formal metalanguage is an artificial language, defined by deductive rules of construction, and used to describe natural languages. The problem of formal metalanguages for linguistic descriptions is a broad topic which we do not mean to-exhaust. We shall restrict ourselves to clarifying the role of formal metalanguages in constructing generative grammars. Every generative grammar is a formal theory. For example, a generative grammar of Russian is a formal theory of Russian, a generative grammar of English is a formal theory of English. We shall focus our attention on the question of correlation between formal metalanguages and formal linguistic theories understood as generative grammars. Let us take a concrete example: formal metalanguage and formal theory as two aspects of applicative generative grammar. This concrete example will make it possible, we hope, to draw certain general conclusions about the role of formal metalanguages in generative grammar. We shall start with formal metalanguage in applicative generative grammar. We call this metalanguage a universal operator language. The universal operator language is defined by the grammar which is an ordered quadruple