Module mz_transform::threshold_elision

Remove Threshold operators when we are certain no records have negative multiplicity.

If we have Threshold(A - Subset(A)) and we believe that A has no negative multiplicities, then we can replace this with A - Subset(A).

The Subset(X) notation means that the collection is a multiset subset of X: multiplicities of each record in Subset(X) are at most that of X.

Structs

• ThresholdElision
  Remove Threshold operators that have no effect.

Functions

• is_superset_of
  Returns true iff rhs is always a subset of lhs.