Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

could any one give me hint for this one?

$G$ be a connected group, and let $H$ be a discrete normal subgroup of $G$, then we need to show $H$ is contained in the center of $G$

first of all, I have no clear idea what is meant by discrete subgroup and its any special properties?

share|improve this question
    
A discrete subgroup is just a subgroup such that the subspace topology it gets as a subset of $G$ is the same as the discrete topology. –  Zev Chonoles Jan 26 '13 at 6:59
    
an example will be appreciated –  Une Femme Douce Jan 26 '13 at 7:00
    
An example: circle group and $n$-th root of unity. –  user27126 Jan 26 '13 at 7:07
    
Hint: Fix $h \in H$. What must the set $ghg^{-1}$ be, using connectedness? –  user27126 Jan 26 '13 at 7:08

1 Answer 1

up vote 3 down vote accepted

Hint, See: Lecture V - Topological Groups, Theorem 5.5.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.