Wednesday is a proof test! It will be an existence proof. For more practice, see Hammack, Chapter 7, exercises 12, 17, 18, 20 (uses the symbol “divides”; it says “11 divides 2^n-1”).

Finish your existence proofs worksheet; choose one of them to request feedback on from the grader (put it first in what you hand in). In class we will take up the solutions. (Of course, don’t look at this before you do your proof for feedback, that would be kind of silly.)

With what time remains, read Hamkins, Chapter 3 up to end of 3.2 (Number Theory, Prime Numbers and Fundamental Theory of Arithmetic). This involves an existence proof.