Categories

The textbook for the course is Rudin’s book, one of the most classic introductory books in analysis. As I need to grade several problems from the exercises part, I read through the first chapter and kept in mind what results students can use in their proofs. But quickly, I was stuck at the point where students started to use things like, if $a=b$, then $ac=bc$ or if $a=b$ then $a+c=b+c$.