Before revision: Namely, each clone C in Post's lattice which contains at least one constant function corresponds to two clones under the less restrictive definition: C, and C together with all nullary functions whose unary versions are in C. If one only considers clones that contain the constant functions, the classification is much simpler .
After revision: : there are only 7 such clones: 'UM, Λ, V, U, A, M, ⊤``Namely, each clone C in Post's lattice which contains at least one constant function corresponds to two clones under the less restrictive definition: C, and C together with all nullary functions whose unary versions are in C. If one only considers clones that contain the constant functions, the classification is much simpler .