A rule known as ground if all of its atoms (head and overall body) are floor. A floor rule R1 is a ground occasion of A further rule R2 if R1 is the result of a substitution of constants for every one of the variables in R2. The Herbrand foundation https://connervpjbs.csublogs.com/40815011/the-fact-about-datalog-that-no-one-is-suggesting