For today, the RNPLS&T’s single network of classifications comprises four classification systems, i. e. State Rubicator of Sci-tech Information (GRNTI, version 2021) as the network foundation and core of the State System of Sci-tech Information, UDC (UDC tables in Russian), Classification Codes of the Higher Attestation Commission, WoS categories and subject areas, and international OECD classification. The semantic matches between the GRNTI headings and codes of the other classifications are defined as logical matching relations, extension inclusion and overlapping including that of key terms and word combinations used for indexing the thematic subject. Three types of semantic relations are determined: equivalency, hierarchy, and association. The statistics of matches in hierarchical levels of GRNTI thematic sections are cited. Based on the statistical analysis, the principal type of semantic matches is identified, along with the largest ratios for every type of relations for each of the classification under examination. The functional options for the single networked headings as the system of interrelated classifications of science objects are demonstrated as exemplified by crossrubrication of subject areas within the Critical Technologies List.