Decrease. The Hint operator may change a large number of member areas, up or down, but the two variants on that operator will only increase member areas because they are only applied if the unity check is greater than one. The Decrease operator attempts to balance those by providing a mechanism for reducing sizes. With a probability given by a parameter, the size of a member whose unity check is less than one will be decreased to the next lower allowed size. We instantiated this operator with a probability of 0.01 only.