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6.5 Relational functions that return boolean values

bool Subset(Relation &r, Relation &r)
Works for both relations and sets. The arguments must have the same arity. If and then the result is .
bool Weak_Subset(Relation &r, Relation &r)
Works for both relations and sets. The arguments must have the same arity. If and then the result is B, where . This function will often return true in cases where is a subset of , however it is not guaranteed to. The situations in which weak_subset agrees with exact subset are deliberately not specified as they may change in future releases.



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