Перегляд за автором "Petrenko, O.V."

Сортувати за: Порядок: Результатів:

  • Balleans and G-spaces 
    Petrenko, O.V.; Protasov, I.V. (Український математичний журнал, 2012)
    We show that every ballean (equivalently, coarse structure) on a set X can be determined by some group G of permutations of X and some group ideal I on G. We refine this characterization for some basic classes of balleans ...
  • Ultrafilters on G-spaces 
    Petrenko, O.V.; Protasov, I.V. (Algebra and Discrete Mathematics, 2015)
    For a discrete group G and a discrete G-space X, we identify the Stone-Cech compactifications βG and βX with the sets of all ultrafilters on G and X, and apply the natural action of βG on βX to characterize large, thick, ...