English

The groups $S^3$ and $SO(3)$ have no invariant binary $k$-network

General Topology 2013-11-05 v2 Group Theory

Abstract

A family N\mathcal N of closed subsets of a topological space XX is called a {\em closed kk-network} if for each open set UXU\subset X and a compact subset KUK\subset U there is a finite subfamily FN\mathcal F\subset\mathcal N with K\FNK\subset\bigcup\F\subset \mathcal N. A compact space XX is called {\em supercompact} if it admits a closed kk-network N\mathcal N which is {\em binary} in the sense that each linked subfamily LN\mathcal L\subset\mathcal N is centered. A closed kk-network N\mathcal N in a topological group GG is {\em invariant} if xAyNxAy\in\mathcal N for each ANA\in\mathcal N and x,yGx,y\in G. According to a result of Kubi\'s and Turek, each compact (abelian) topological group admits an (invariant) binary closed kk-network. In this paper we prove that the compact topological groups S3S^3 and \SO(3)\SO(3) admit no invariant binary closed kk-network.

Keywords

Cite

@article{arxiv.1102.4328,
  title  = {The groups $S^3$ and $SO(3)$ have no invariant binary $k$-network},
  author = {Taras Banakh and Slawomir Turek},
  journal= {arXiv preprint arXiv:1102.4328},
  year   = {2013}
}

Comments

5 pages

R2 v1 2026-06-21T17:29:35.215Z