presto-main/src/main/java/io/prestosql/type/setdigest/SetDigest.java/SetDigest/isExact
class SetDigest:    public boolean isExact()
    {
        // There's an ambiguity when minhash.size() == maxHashes, since this could either
        // be an exact set with maxHashes elements, or an inexact one. Which is why strict
        // inequality is used here.
        return minhash.size() < maxHashes;
    }