If you find any mistakes, please make a comment! Thank you.

Surjective group endomorphisms need not be automorphisms

Solution to Abstract Algebra by Dummit & Foote 3rd edition Chapter 1.6 Exercise 1.6.19 Let \$G = \{ z \in \mathbb{C} \ |\ z^n = 1\ \mathrm{for\ some}\ n \in…