Kuratowski monoids of n-topological spaces [article]

T. Banakh, O. Chervak, T. Martynyuk, M. Pylypovych, A. Ravsky, M. Simkiv
2015 arXiv   pre-print
Generalizing the famous 14-set closure-complement Theorem of Kuratowski from 1922, we prove that for a set X endowed with n pairwise comparable topologies τ_1⊂...⊂τ_n, by repeated application of the operations of complement and closure in the topologies τ_1,...,τ_n to a subset A⊂ X we can obtains at most 2K(n)=2∑_i,j=0^ni+jii+jj distinct sets.
arXiv:1508.07703v4 fatcat:clqz52dz3bcxfam6d7frrdomue