Аннотация:
For any countable ring $R$ with discrete topology $\tau_0$ and any countable $R$-module $M$ the lattice of all $(R,\tau_0)$-module topologies contains:
– A sublattice which is isomorphic to the lattice of all real numbers with the usual order;
– Two to the power of continuum $(R,\tau_0)$-module topologies each of which is a coatom.
Ключевые слова и фразы:countable ring, countable module, ring topology, topologies of modules, Hausdorff topology, basis of the filter of neighborhoods, number of topologies of module, the lattice of all topologies of module, coatoms on lattice.