doi:10.1108/EL-02-2023-0052engYagüe, José FélixHuitzil, IgnacioBobed, CarlosBobillo, FernandoFUKG: answering flexible queries over knowledge graphsART-2023-136315Purpose: There is an increasing interest in the use of knowledge graphs to represent real-world knowledge and a common need to manage imprecise knowledge in many real-world applications. This paper aims to study approaches to solve flexible queries over knowledge graphs. Design/methodology/approach: By introducing fuzzy logic in the query answering process, the authors are able to obtain a novel algorithm to solve flexible queries over knowledge graphs. This approach is implemented in the FUzzy Knowledge Graphs system, a software tool with an intuitive user-graphical interface. Findings: This approach makes it possible to reuse semantic web standards (RDF, SPARQL and OWL 2) and builds a fuzzy layer on top of them. The application to a use case shows that the system can aggregate information in different ways by selecting different fusion operators and adapting to different user needs. Originality/value: This approach is more general than similar previous works in the literature and provides a specific way to represent the flexible restrictions (using fuzzy OWL 2 datatypes).2023http://zaguan.unizar.es/record/14901910.1108/EL-02-2023-0052http://zaguan.unizar.es/record/149019oai:zaguan.unizar.es:149019info:eu-repo/grantAgreement/ES/AEI/PID2020-113903RB-I00Electronic library 42, 3 (2023), 368-392by-nchttp://creativecommons.org/licenses/by-nc/3.0/es/info:eu-repo/semantics/openAccess