question start notion find extension g del 's theorems fuzzy logic fuzzy databases fuzzy relations defined possible develop fuzzy relational databases first fuzzy relational database frdb appeared maria zemankova 's dissertation later models arose like buckles petry model prade testemale model umano fukami model gefred model jm medina vila et al fuzzy querying languages defined sqlf p bosc et al fsql j galindo et al languages define structures order
Formal science Computer science Logic in computer science Fuzzy logic