This lecture is part of my Berkeley math 115 course "Introduction to number theory"
For the other lectures in the course see • Introduction to number theory (Berkel...
We give some examples of discriminants where not all forms are equivalent, and show that it is still sometimes possible to wrok out which primes are represented by forms.
The textbook is "An introduction to the theory of numbers" by Niven, Zuckerman, and Montgomery (5th edition).