where is symmetric difference (bitwise XOR). Q 0 thus represents the support for S 0 that can be used for parameter search, noting here that Q 0 has the same number of nodes as S 0 due to the use of ∩ † . Manipulating Q 0 will induce partitions of A since there could be some a ∈ A that is no longer a subset of the modified Q 0 . The manipulations are then applied to S 0 in order to find a new SMARTS pattern S j , where j refers to an index of all manipulations considered (Fig. ).