Previous |  Up |  Next

Article

Keywords:
cardinal function; almost P-space
Summary:
Motivated by some examples, we introduce the concept of special almost P-space and show, using the reflection principle, that for every space $X$ of this kind the inequality ``$|X| \leq \psi_{c}(X)^{t(X)}$" holds.
References:
[1] Dow A.: An introduction to applications of elementary submodels to topology. Topology Proc. 13 (1988), 17-72. MR 1031969 | Zbl 0696.03024
[2] Dow A.: More set-theory for topologists. Topology Appl. 64 (1995), 243-300. MR 1342520 | Zbl 0837.54001
[3] Engelking R.: General Topology. Heldermann Verlag, Berlin, 1989. MR 1039321 | Zbl 0684.54001
[4] Fedeli A., Watson S.: Elementary submodels and cardinal functions. Topology Proc., to appear. MR 1429175 | Zbl 0894.54008
[5] Hodel R.E.: Cardinal Functions I. in: Handbook of Set-theoretic Topology, (Kunen K. and Vaughan J.E., eds.), North Holland, 1984, pp.1-61. MR 0776620 | Zbl 0559.54003
[6] Juhàsz I.: Cardinal Functions in Topology-ten years later. Mathematical Centre Tracts 123, Amsterdam, 1980. MR 0576927
[7] Levy R.: Almost P-spaces. Can. J. Math. 29 (1977), 284-288. MR 0464203 | Zbl 0342.54032
[8] van Mill J.: An introduction to $\betaømega$. in: Handbook of Set-theoretic Topology, (Kunen K. and Vaughan J.E., eds.), North Holland, 1984, pp.503-567. MR 0776630
[9] Watson S.: The construction of topological spaces: Planks and Resolutions. in: Recent Progress in General Topology (Hušek M. and Van Mill J., eds.), North Holland, 1992, pp.675-757. MR 1229141 | Zbl 0803.54001
[10] Watson S.: The Lindelöf number of a power; an introduction to the use of elementary submodels in general topology. Topology Appl. 58 (1994), 25-342. MR 1280708 | Zbl 0836.54004
Partner of
EuDML logo