Which of the following is/are not true?
1
The automorphism group Aut (ℤ2 × ℤ2) is abelian.
2
There is a non trivial group homomorphism from ℂ to ℝ
3
All non-trivial proper subgroups of (ℝ, +) are cyclic.
4
Every infinite abelian group has at least one element of infinite order.