Galois theory: Introduction

This lecture is part of an online course on Galois theory. This is an introductory lecture, giving an informal overview of Galois theory. We discuss some historical examples of problems that it was used to solve, such as the Abel-Ruffini theorem that degree 5 polynomials cannot in general be solved by radicals, and Wiles's proof of Fermat's last theorem. The classic book "Galois theory" by E. Artin has been reprinted by Dover and is strongly recommended. Correction: As pointed out by ben1996123 the product for Delta at 16:55 is missing a 24th power. For the full lecture course on Galois theory see    • Galois theory   For the group theory used in the course see    • Group theory