Let (G, ∘) and (G', *) be two groups and Φ : G → G' be an epimorphism. Then Φ is an isomorphism if and only if-
1
Ker Φ ⊂ {eG}
2
Ker Φ ⊂ {eG'}
3
Ker Φ = {eG}
4
Ker Φ = { eG'}
Let (G, ∘) and (G', *) be two groups and Φ : G → G' be an epimorphism. Then Φ is an isomorphism if and only if-