Application of sentence parsing for determining keywords in Ukrainian texts

The article presents the use of generative grammars in linguistic modeling. A description of sentence syntax modeling is used to automate the process of analysis and synthesis of natural language texts. The article reveals the features of synthesizing sentences of different languages with the use of generative grammars. The article examines influence of norms and rules of a language on the process of constructing grammars. The use of generative grammars has great potential in the development and creation of automated systems for text content processing, linguistic support for linguistic computer systems etc. In natural languages there are situations where notions, which are dependent on the context, are described as independent of context, i.e. in terms of context-free grammars. This description is complicated by the formation of new categories and rules. The article features the process of introducing new restrictions on these grammar classes through the introduction of new rules. Uncut grammars were received if the number of characters in the right part of the rules were not less than the number of characters in the left one. Then by replacing the only character a context-sensitive grammar was received. A grammar with only one character in the left part of the rule is called a context-free grammar. No further natural restrictions may be applied to the left part of a rule. Based on the importance of automatic processing of text content in modern information media (e.g., information retrieval systems, machine translation, semantic, statistical, optical and acoustic analysis and speech synthesis, automated editing, extracting knowledge from text content, abstracting and annotating text content, indexing text content, teaching and didactic, management of linguistic corpora, various tools for lexicography, etc.), specialists are actively looking for new models, ways of their description and methods of automatic processing of text content. One of such methods lies in developing general principles of syntactic lexicographical systems formation and developing mentioned systems of processing text content for specific languages based in these principles. Any parsing tools consist of two parts: a knowledge base of concrete natural language and parsing algorithm, i.e. a set of standard operators of text content processing based on this knowledge. The source of grammatical knowledge is data of morphological analysis and various tables filled with concepts and linguistic units. They are the result of an empirical study of the text content in natural language by experts aiming at highlighting the basic laws for parsing.