Hierarchical clustering of the readings of the members of the Society of United Slavs using fuzzy set theory methods

The subject of the research presented in this article is the testimonies of members of the Society of United Slavs regarding the murder of the royal family. The article accumulates all testimonies from members of the Society that touch upon the issue of the intent to murder the royal family. The focus of the study in the article is the degree of radicalization among the members of the Society of United Slavs and the degree of similarity in their views on the proposed methods of the Society. The authors employ expert evaluation methods for an objective interpretation of each participant's testimony and to uncover their understandings of the goals of the Society of United Slavs. Subsequently, the authors apply methods from fuzzy set theory to construct an objective hierarchical clustering of the members of the Society, to demonstrate the internal connections that existed among the participants based on the similarity or dissimilarity of their views. The hierarchical clustering of the members of the Society is based on their testimonies. The authors establish an objective scale of radicalism for the testimonies of each member of the Society and introduce a measure of similarity of their testimonies, on the basis of which clustering is further constructed using the transitive closure of the introduced relation. The main conclusion of the presented work is that within the Society of United Slavs, two clusters were identified, wherein the Decembrists held diametrically opposed views regarding the permissible methods of achieving the Society's goals. The first cluster is centered on Decembrist I.I. Gorbachyovsky and includes Decembrists N.F. Lisovsky and I.V. Kiriev. Members of this cluster were convinced that the Society planned the murder of the royal family and were willing to adhere to this idea until the end. The second cluster included P.I. Borisov and A.I. Tyutchev, who were confident that the murder of the royal family was not intended. The scientific novelty of the work lies in the fact that it is the first time that fuzzy set theory has been applied to the method of hierarchical clustering of members of the Society of United Slavs.