 Second, Isom takes a particularly interesting form for monadic quantifiers. If \(\M = (M,A_1,\ldots,A_k)\), where \(A_i \subseteq M\) for each i, then \(A_1,\ldots,A_k\) partition M into \(2^k\) pairwise disjoint subsets (some of which may be empty); let us call them the parts of \(\M\). We illustrate with \(k=2\) and \(\M = (M,A,B)\):