11
votes
Accepted
Is there a topological group with the small index property that does not have automatic continuity?
Here is a counterexample. Consider $\mathbb{R}$ with addition. We define a topology on this group by giving the cosets of all countable index subgroups as a sub-basis.
This subbasis is actually a ...
- 406
Only top scored, non community-wiki answers of a minimum length are eligible