Catch up on any stuff you haven’t done yet from recent posts! See you in class.

Today’s recommendation for more on Godel’s theorem was the book *Godel, Escher, Bach* by Douglas Hofstadter.

Catch up on any stuff you haven’t done yet from recent posts! See you in class.

Today’s recommendation for more on Godel’s theorem was the book *Godel, Escher, Bach* by Douglas Hofstadter.

We delayed the contradiction quiz by popular vote because we were having productive discussions in class. It will be today. See the last post for info.

**To do for class today:**

- Prepare for contradiction quiz.
- Do practice problems from Hammack, Sections 11.1, 11.2 as needed (i.e. until they are super easy).
- On Friday we did new groups by random selection. Contact me if you do not have a new group because you missed class.

**Group Presentation Day.**

**Quiz on Proof by Contradiction** (as noted in last post). Prepare by doing examples from your book and working on the suggested examples posted here.

**QUIZ TODAY**: Badges (all). Last chance on sets & logic in class. If you still miss them, there’s an opportunity to earn the badge by visiting me in office hours to demonstrate mastery. More on that after the quiz.

**Quiz coming up on Friday:** a proof by contradiction. Prepare by doing examples from your book and working on the suggested examples posted here.

**To do for class:**

- Prepare for the quizzes coming up.
- Also, suggested exercises of Chapter 7 covering many different methods of proof (so choosing the correct method is part of it), which you should do sometime this week: 2, 8, 10, 12, 17, 21, 28.
- Also, when time allows this week: reading on relations: Section 11 up to end of 11.1

**Happy Halloween!** Please feel welcome to wear a math costume to class (non-math costumes are alright too, but who would do that?).

**Notes:**

- On Wed we’ll do a badges quiz with the last sets/logic; I’ll return this week’s one on Monday. If you are still missing sets/logic badges after that you can demonstrate mastery one-on-one in my office hours.
- It was pointed out it is time for new groups. I’m going to put this off for one week; so we’ll make new groups on Friday.

**To do for class:**

- Read your textbook, Section 7. This covers some variations on the theme of proof: if-and-only-if (just two if-thens), equivalent statements (piles of if-thens), existence proofs (show the relevant example), and the concept of constructive or non-constructive proof (we encountered this with CHOMP).

Today is a group presentation day.

I will pick groups to present as usual, but if you haven’t had a chance to present, and would like to make sure you get a chance, you can request to present, either for this week’s group-work, or you can choose something you’d like to present (e.g. from Wednesday’s worksheet or a proof we didn’t cover another time), and **email me ahead of time that you’d like to do this**.

Also, next week will probably be the last in-class chance for sets and logic badges, but you will be welcome to come to my office during office hours to demonstrate your understanding of a badge you have missed before the end of term. I’ll set details after the last in-class opportunity.

**Quiz:** Badges quiz. This will have proof setups and counting. I will give a ***second last chance*** on all sets and logic badges.

**To do for class:**

- Tabulate for yourself which badges you have earned, and decide which ones you need to work on. Study those topics.
- Compare the badges you believe you have earned with my record on D2L, and bring your past quiz as evidence to report the discrepancy to me.
*I believe I missed recording one badges quiz, so this is crucial!* - Please bring your contradiction quiz for me to input grades also, if you haven’t yet. Sorry for the mixup on this — I forgot to record the fourth proof quiz (contradiction) quiz grades and need you to show them to me again.

**To do for class today:**

- Here are the worksheets for counting from class last week: first and second.
- Please try to complete the worksheets as far as possible. On the first, make sure you are confident of your answers on questions 1-7 at least. On the second, make sure you are confident of your answers on sections 1 and 2, at least.
- You may wish to read some or all of Hammack, Chapter 3. We do counting a little differently (with an emphasis on the process, not on the formalism of lists, sets, factorials and subsets), so if you find Hammack is too much of a departure, then just focus on understanding the worksheets by discussing them with me and with your group.

Presentation day. Thanks all!

**Special Announcement:** I’m giving a math club talk Wednesday afternoon. See here. It is about cryptography.

Sorry that I forgot to give out the quiz on Monday, I really have trouble reading the clock. Worse than that, **I forgot to record the grades on the quiz for contradiction.**

**Quiz today:** Induction. See Monday’s daily post for review problems to do in preparation. This will be a weak induction involving a formula.

**To do for today:**

- Prepare for your induction quiz! (See Monday’s post for suggestions)