Condensations onto σ-Compact Spaces

被引:0
作者
Lipin, A. E. [1 ,2 ]
Osipov, A., V [1 ,2 ]
机构
[1] Russian Acad Sci, Krasovskii Inst Math & Mech, Ural Branch, Ekaterinburg, Russia
[2] Ural Fed Univ, Ekaterinburg, Russia
关键词
condensation; Polish space; compact space; sigma-compact space; a(iota) -space;
D O I
10.1134/S1064562422050167
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
In this paper, we prove the following result. Let Xbe a complete metric space of weight w(X) and H subset of X be a set such that w(X) < |H| < c. Then there is no continuous bijection of the subspace X\H onto a a -compact space. As a result, there is no continuous bijection of the subspace X\H onto a Polish space. Thus, it has been proved that metric compact spaces are not a(iota) -spaces for any uncountable cardinal number iota. This result answers the question asked by E.G. Pytkeev in his coauthored work "On the properties of subclasses of weakly dyadic compact sets" to be published in the Siberian Mathematical Journal.
引用
收藏
页码:351 / 355
页数:5
相关论文
共 11 条
  • [1] Some Properties of Subcompact Spaces
    Belugin, V., I
    Osipov, A., V
    Pytkeev, E. G.
    [J]. MATHEMATICAL NOTES, 2022, 111 (1-2) : 193 - 203
  • [2] Belugin VI, 2021, MATH NOTES+, V109, P849, DOI [10.4213/mzm12499, 10.1134/S0001434621050187]
  • [3] COMPACT CONDENSATIONS OF HAUSDORFF SPACES
    Belugin, V. I.
    Osipov, A. V.
    Pytkeev, E. G.
    [J]. ACTA MATHEMATICA HUNGARICA, 2021, 164 (01) : 15 - 27
  • [4] Belugin V. I., 2022, IN PRESS
  • [5] Engelking R., 1983, GEN TOPOLOGY
  • [6] KURATOWSKI K., 1966, TOPOLOGY, V1
  • [7] Parkhomenko A. S., 1941, IZV AKAD NAUK SSSR M, V5, P225
  • [8] PYTKEEV EG, 1976, MATH NOTES+, V20, P831, DOI 10.1007/BF01098898
  • [9] PYTKEEV EG, 1977, DOKL AKAD NAUK SSSR+, V233, P1046
  • [10] RAUKHVARGER IL, 1949, DOKL AKAD NAUK SSSR+, V66, P13