Removing an element from this simple Bloom filter is impossible because there is no way to tell which of the bits it maps to should be cleared. Although setting any one of those bits to zero suffices to remove the element, it would also remove any other elements that happen to map onto that bit. Since the simple algorithm provides no way to determine whether any other elements have been added that affect the bits for the element to be removed, clearing any of the bits would introduce the possibility of false negatives.