Ultrafilters and Decompositions of Abelian Groups

  • I. V. Protasov Kyiv Nat. Taras Shevchenko Univ.


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.
How to Cite
Protasov, I. V. “Ultrafilters and Decompositions of Abelian Groups”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 53, no. 1, Jan. 2001, pp. 85-93, https://umj.imath.kiev.ua/index.php/umj/article/view/4224.
Research articles