Article
Keywords:
$\Sigma$-product; Tikhonov cube; Valdivia compact; locally compact space
Summary:
In some sense, a dual property to that of Valdivia compact is considered, namely the property to be embedded as a closed subspace into a complement of a $\Sigma$-subproduct of a Tikhonov cube. All locally compact spaces are co-Valdivia spaces (and only those among metrizable spaces or spaces having countable type). There are paracompact non-locally compact co-Valdivia spaces. A possibly new type of ultrafilters lying in between P-ultrafilters and weak P-ultrafilters is introduced. Under Martin axiom and negation of CH, no countable nowhere dense space is a co-Valdivia space.
References:
[1] Arhangel'skii A.V.:
Two types of remainders of topological groups. Comment. Math. Univ. Carolin. 49 (2008), 119-126.
MR 2433629 |
Zbl 1212.54086
[3] Kalenda O.:
Valdivia compact spaces in topology and Banach space theory. Extracta Math. 15 (2000), 1-85.
MR 1792980 |
Zbl 0983.46021
[4] Kalenda O.:
On the class of continuous images of Valdivia compacta. Extracta Math. 18 (2003), 65-80.
MR 1989298 |
Zbl 1159.46306
[6] Šapirovskii B.:
On the density of topological spaces. Soviet Math. Dokl. 13 (1972), 1271-1275.
MR 0383331
[7] Šapirovskii B.:
On separability and metrizability of spaces with Souslin's condition. Soviet Math. Dokl. 13 (1972), 1633-1638.
MR 0322801