No submaximal topology on a countable set is T-1-complementary

Citation
Mg. Tkacenko et al., No submaximal topology on a countable set is T-1-complementary, P AM MATH S, 128(1), 2000, pp. 287-297
Citations number
11
Categorie Soggetti
Mathematics
Journal title
PROCEEDINGS OF THE AMERICAN MATHEMATICAL SOCIETY
ISSN journal
00029939 → ACNP
Volume
128
Issue
1
Year of publication
2000
Pages
287 - 297
Database
ISI
SICI code
0002-9939(200001)128:1<287:NSTOAC>2.0.ZU;2-M
Abstract
Two T-1-topologies tau and mu given on the same set X, are called transvers al if their union generates the discrete topology on X. The topologies tau and mu are T-1-complementary if they are transversal and their intersection is the cofinite topology on X. We establish that for any connected Tychono ff topology there exists a connected Tychonoff transversal one. Another res ult is that no T-1-complementary topology exists for the maximal topology c onstructed by van Douwen on the rational numbers. This gives a negative ans wer to Problem 162 from Open Problems in Topology (1990).