3.1.1DefinitionofFD-pp68Section3.1.1 LetRbearelationschemeandX,YbesetsofattributesinR. AfunctionaldependencyfromXtoYexistsifandonlyif: Foreveryinstanceof|R|ofR,iftwotuplesin|R|agreeonthevaluesoftheattributesinX,thentheyagreeonthevaluesoftheattributesinY ...