I just read about short topic about simple group and I found problem about
center of simple abelian group and nonabelian
From definition of simple, it must have no proper non trivial normal subgroup.
In Abelian group case since Abelian group always normal that means the center must be a whole group only.
Since simple group's condition does not allow no proper non trivial normal subgroup.
But How about non abelian group case ? Is it {e} only ? since simple group's condition restrict nontrivial normal subgroup. Or it's does not exist?