Some new basic concepts are proposed in this paper, including the approximation space of generalization, rough approximation axiom, disturbance set axiom, classification principle of rough set, principle of nondeterministic even set, principle of concentration, game classification, quantum logic classification, bit quantum symmetric classification, incomparable set, bit space set, protocol relation, rough set function of protocol relation, rough classification algebra, rough simple algebra, etc. , and a guess is also proposed. The mathematics viewpoints of knowledge are shown. Based on the protocol relation, the rough quotient algebra and the rough subalgebra are constructed. The avoidance-merge algorithm (A - M algorithm) is presented and an example is given.