Combined method for plagiarism detection in text documents

There are two global approaches to the problem of searching plagiarism in the text: external and intrinsic search. The first approach implies search through an external collection of documents that could have been used for text reuse. The second approach, on the contrary, does not use any external data, but analyzes the text by itself. It is proposed to combine these two approaches to speed up the search for text plagiarism. With a large flow of documents that need to be checked, the outer corpus search system processes each document and finds plagiarised blocks in each document, if there are any. However, intrinsic search could be used to determine the fact of plagiarism. Thus, it is possible to reduce the number of documents for the expensive procedure for searching for plagiarism by the outer corpus. Moreover, in an isolated analysis of a single document, there is no need to try to find specific blocks of plagiarism, this procedure is considered as a unique indicator of the originality of the document. If the overall originality is at a low level, then this document should be sent for a more detailed and accurate check. The proposed method allows to filter texts with a high rate of originality that do not need additional verification.