Abstract
<jats:p>Closed classes under superposition are examined in π-valued logic. E. Post established that the lattice (on inclusion) of all closed classes in two-valued logic is countable. Besides, each closed class has a finite basis in two-valued logic. Yu. I. Yanov and A. A. Muchnick proved that the lattice of all closed classes in π-valued logic is continuous at each π > 3. Besides, there are closed classes without a basis and closes classes of a countable basis in π-valued logic at π > 3. Because of the continuity on the lattice of all closed classes at π > 3, its sub-lattices are examined. In particular, the closed class of all functions, that are represented by polynomials modulo π, is considered in π-valued logic. This closed class contains all functions of π-valued logic, if and only if π is a prime number. If π is a composite number, then this closed class is not even pre-complete. In works of A. N. Cherepov, A. B. Remizov, A. A. Krokhin, K. L. Safin, E. V. Sukhanov, D. G. Meschaninov and of others the structure of sub-lattices and of over-lattices is examined for the closed class of all polynomial functions at composites π. In this work at each composite number π the continuity of the sub-lattice is established for the closed class of all polynomial functions in π-valued logic.</jats:p>