Direct and Inverse Problems of Information Retrieval of Text Documents

Information retrieval on the Web, databases and other sources of text documents includes tasks that require analyzing the relationships between documents and the constituent elements of documents. Establishing such relations allows search engine users to retrieve the documents they need from endless sources of information using concise search request, as well as to choose effective methods of processing found documents to solve various tasks of analyzing the content of documents. A classification of methods for processing text documents using forward and reverse indices is proposed, which allows generalizing the properties of document search and processing methods. Elementary examples of application of the methods are given, which allow the reader to en-ter the essence of the issues quickly, discussed in the article, and tounderstand better the prin-ciples of construction of these methods and their suitability for solving specific information re-trieval tasks.