Some remarks on non-separable gaps in P(ω)/fin

Magdalena Grzech

Abstrakt

The Hausdorff gap is the well known example of a non-separable, increasingly ordered gap in P(ω)/fin. In this paper new construction of a non-separable gap in P(ω)/fin is presented.

Słowa kluczowe: Boolean algebra, Cech-Stone compactification, gap
References

Comfort W.W., Negrepontis S., The theory of ultrfilters, Springer Verlag, New York 1974.

Hausdorff Summen von Mengen F1, Fund. Math. 26, 1936, 241-255.

Hechler S., On existence of certain cofinal subsets of, Axiomatic Set Theory, T. Jech (ed.), Proc. Symp. Pure Math. vol. 13 II, 1974, 155-173.

Jech T., Set Theory, Academic Press, New York et al., 1978.

Kunen K., Weak P-points in N*, Colloq. Math. soc. Jano’s Bolyai 23, Topology, Budapest 1978, 741-749.

Rothberger F., Une remarque concernant l’hipotése du continu, Fund. Math. 31, 1939, 224-226.