May 17th, 2019, 04:47 AM  #1 
Member Joined: Apr 2017 From: India Posts: 73 Thanks: 0  Quotient group
If G/H is abelian, where H is a normal subgroup of G, then H is abelian. True or False. This question seems confusing, as I know if G/H is abelian, then it cannot be deduced whether G is abelian or not. That is it may happen that, if G/H is abelian, then G may not be so. But how to check whether H will be abelian or not. I know that H is a normal subgroup and all normal subgroups are not commutative. H is simply a normal subgroup, therefore nothing can be deduced for H. The statement should stand as false. Is my attempt correct? or Incorrect? Another perspective: If G/H is abelian, then G may or may not be abelian. Suppose, if G is abelian, then every subgroup of an abelian group is abelian and therefore H will be abelian. However, if G is nonabelian, then I can't say anything about the nature of H and hence the statement is incorrect. Is my attempt correct? or Incorrect? Last edited by shashank dwivedi; May 17th, 2019 at 04:51 AM. 
May 17th, 2019, 06:56 PM  #2 
Member Joined: Jan 2016 From: Athens, OH Posts: 93 Thanks: 48 
To prove the statement false, all you need is one example. So let $G=S_4$ and $H=A_4$.


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