Ultrafilters and Decompositions of Abelian Groups
We prove that every PS-ultrafilter on a group without second-order elements is a Ramsey ultrafilter. For an arbitrary PS-ultrafilter ϕ on a countable group G, we construct a mapping f: G → ω such that f(ϕ) is a P-point in the space ω*. We determine a new class of subselective ultrafilters, which is considerably wider than the class of PS-ultrafilters.
English version (Springer): Ukrainian Mathematical Journal 53 (2001), no. 1, pp 99-107.
Citation Example: Protasov I. V. Ultrafilters and Decompositions of Abelian Groups // Ukr. Mat. Zh. - 2001. - 53, № 1. - pp. 85-93.