knownaboutthesizeofthesmallestnitemodelsofasatis-ableguardedsentence - PPT Presentation
x8
y
x
y9
z
x
zwhere
x
yand
x
zareconjunctionsofatomsoverRcalledthebodyandtheheadofrespectivelyItiswellknownthatdatabasequeryansweringunderTGDsisundecidablesee17evenforve ID: 98773