allNegatedLiteralsVariablesInNonNegatedLiteralsToo

Whether every variable occurring in one of this Clause's negatedBodyLiterals also occurs in at least one of its nonNegatedBodyLiterals — the usual Datalog "safe negation" condition. It guarantees a negated literal such as not(q(Y)) is only ever checked once Y has already been bound to one of finitely many values by a positive goal earlier in the body, rather than requiring q to be enumerated over its (potentially infinite) universe of terms.