Wiener Norbert. Cybernetics. Or control and communication in the animal and the machine. The Technology Press; John Wiley & Sons, Inc., New York; Hermann et Сie, Paris; 1948, 194 pp.

condition that a be logically expressible, in the large sense, in the predicates P, is that it remain invariant for all the automorphisms of the sys tem. 2. Given a system [U; P], and a subset A of U, each predicate, a, of type 1, deter minate in A, is uniquely decomposable into a disjunction of predicates each irreducible in A and each of which has as solution the elements of one of the cells of transitivity deter mined within the totality of solutions of a, by its Galois subgroup with respect to A. Hints are given of several interesting problems concerning the logical structure of known abstract mathematical systems, and equivalences among them.