9-24 & 9-29 Feedback

• Use [[$\gcd(a,b)$]] for $\gcd(a,b)$
• if you are consistently adding homework problems, you should give someone else a chance to add the hw solutions.
• don’t forget spaces between your sentences
• in HW5 Problem 10, you’ve skipped some steps between the equalities in the proof $Z(G)$ is closed. This should be corrected. It’s also unnecessary to show the operation is associative on $Z(G)$ , since this follows from the associativity of $*$ on $G$.
• If you are adding a theorem and proof from the book, it’s fine to copy the proof from the text, but remember that we want the wiki to be self-contained. So, if the proof in the book refers to comments before another item in the book, you should include those comments in your proof.
• the definition of automorphism should include the word automorphism. The informal definition is not a complete sentence, and is therefore unclear. Similarly, the non-examples are also unclear. What is the map that isn’t an automorphism? What are Q and R?
• In hw2 problem 12(b), you should say you are looking at the specific functions $f(x)=2x, g(x)=x$