unionUniqSets, unionManyUniqSets, minusUniqSet,
elementOfUniqSet, mapUniqSet, intersectUniqSets,
isEmptyUniqSet, filterUniqSet, sizeUniqSet, foldUniqSet,
unionUniqSets, unionManyUniqSets, minusUniqSet,
elementOfUniqSet, mapUniqSet, intersectUniqSets,
isEmptyUniqSet, filterUniqSet, sizeUniqSet, foldUniqSet,