RT Journal Article T1 Approaching the square of opposition in terms of the f-indexes of inclusion and contradiction A1 Madrid-Labrador, Nicolás Miguel A1 Ojeda-Aciego, Manuel K1 Matemáticas aplicadas AB We continue our research line on the analysis of the properties of the f-indexes of inclusion and contradiction; in this paper, specifically, we show that both notions can be related by means of the, conveniently reformulated, Aristotelian square of opposition. We firstly show that the extreme cases of the f-indexes of inclusion and contradiction coincide with the vertexes of the Aristotelian square of opposition in the crisp case; then, we allocate the rest of f-indexes in the diagonals of the extreme cases and we prove that the Contradiction, Contrariety, Subcontrariety, Subalternation and Superalternation relations also hold between the f-indexes of inclusion and contradiction. PB Elsevier YR 2023 FD 2023-10-31 LK https://hdl.handle.net/10630/28805 UL https://hdl.handle.net/10630/28805 LA eng NO Nicolás Madrid, Manuel Ojeda-Aciego, Approaching the square of opposition in terms of the f-indexes of inclusion and contradiction, Fuzzy Sets and Systems, Volume 476, 2024, 108769, ISSN 0165-0114, https://doi.org/10.1016/j.fss.2023.108769 NO Funding for open Access charge: Universidad de Málaga / CBUA.Partially supported by the Ministry of Science, Innovation, and Universities (MCIU), the State Agency of Research (AEI) and the European Social Fund (FEDER) through the research projects PGC2018-095869-B-I00 (MCIU/AEI/FEDER, UE) and VALID (PID2022-140630NB-I00 MCIN/AEI/10.13039/501100011033), and by Junta de Andalucía, Universidad de Málaga and the European Social Fund (FEDER) through the research project UMA2018-FEDERJA-001. DS RIUMA. Repositorio Institucional de la Universidad de Málaga RD 20 ene 2026