The prime form of a pc set is the identification of the fundamental set type, regardless of transposion and/or inversion. This is an efficient way each of the possible unordered pc sets. To determine the prime form of a pc set, simply transpose the best normal order of the set so that the first number becomes 0. For example: to determine the prime form of the pc set {4,5,8,10}, you would transpose it so that the first number is 0. To do this, subtract the first number from every pc in the set.

                4  5  8  10
              - 4  4  4   4
                0  1  4   6

The prime form of this set is (0146). Note the prime form is notated using parantheses and no commas between the numbers.