Ordinals in topological groups

Raushan Z. Buzyakova

Fundamenta Mathematicae, Tome 193 (2007), p. 127-138 / Harvested from The Polish Digital Mathematics Library

Résumé

We show that if an uncountable regular cardinal τ and τ + 1 embed in a topological group G as closed subspaces then G is not normal. We also prove that an uncountable regular cardinal cannot be embedded in a torsion free Abelian group that is hereditarily normal. These results are corollaries to our main results about ordinals in topological groups. To state the main results, let τ be an uncountable regular cardinal and G a T₁ topological group. We prove, among others, the following statements: (1) If τ and τ + 1 embed closedly in G then τ × (τ + 1) embeds closedly in G; (2) If τ embeds in G, G is Abelian, and the order of every non-neutral element of G is greater than $2^{N} - 1$ then $∏_{i∈N}τ$ embeds in G; (3) The previous statement holds if τ is replaced by τ + 1; (4) If G is Abelian, algebraically generated by τ + 1 ⊂ G, and the order of every element does not exceed $2^{N} - 1$ then $∏_{i∈N}(τ+1)$ is not embeddable in G.

Détail

Publié le : 2007-01-01

Zbl 1133.54022

EUDML-ID : urn:eudml:doc:286129