whereNisabinarymatrix,Visasetofcontextualelements associatedinaone-to-onemannerwiththeverticalindex setIsofN,H isasetofcontextualelementsassociated inaone-to-onemannerwiththehorizontalindexsetI, ofN,andIisacontextualrelationassociatedwiththe binaryrelation9inducedonI,xI,byN.ThesetVis calledtheverticalindexsetofthemodel,andH isits horizontalindexset.ThecontextualrelationI iscalled themodelrelation,andthematrixN iscalledthemodel matrix.Also,N mayoftenbegivenaspecificnamefora specifickindofbinary-matrixmodel.