A rule is known as floor if all of its atoms (head and human body) are ground. A ground rule R1 is really a floor instance of A different rule R2 if R1 is the results of a substitution of constants for all the variables in R2. The Herbrand foundation https://datalog572693.theblogfairy.com/33233305/how-much-you-need-to-expect-you-ll-pay-for-a-good-datalog-5