Abstract:
The $A$-closure in the set $P_k$ of functions of $k$-valued logic is defined
as the closure with respect to the operations of superposition and passing
to the dual functions for even permutations of the set
$E_k=\{0,1,\ldots, k-1\}$. For
any $k$, $k\ge4$, all $A$-closed classes of $P_k$ containing constants
are described. As a corollary, we obtain the description of all
$A$-closed classes contained in the Slupecki class as well as
an $A$-classification of the symmetric
semigroup of mappings of the set $E_k$ into itself. This research was supported by the Russian Foundation for Basic Research,
grant 97–01–00089.