protected override ImmSet <T> Intersect(ImmSet <T> other)
{
return(Root.Intersect(other.Root, Lineage.Mutable(), null).Wrap(EqualityComparer));
}
protected override ImmMap <TKey, TValue> Join(ImmMap <TKey, TValue> other,
ValueSelector <TKey, TValue, TValue, TValue> collision = null)
{
return(_root.Intersect(other._root, Lineage.Mutable(), collision).WrapMap(_equality));
}