Cardinality of the Continuum of Closed Superclasses of Some Minimal Classes in the Partially Ordered Set $${\cal L}_2^3$$
A. V. Makarov, V. V. Makarov · Moscow University Mathematics Bulletin · 2019
It is proved that the set of closed classes containing some minimal classes in the partially ordered set $${\cal L}_2^3$$ of closed classes in the three-valued logic that can be homomorphically mapped onto the two-valued logic has the cardinality of continuum.