Monday, February 12th


  • I realized when administering the quiz on Friday that it was confusing what I was after, in terms of what you can and cannot use.  That’s poor quiz design on my part.  Therefore we’ll have a “re-do”.
  • You can download a copy of the quiz, print it out, and write up your best proof for handing in on Monday.  This will replace your in-class quiz for grading.  This is optional (if you don’t hand something in, I’ll use the quiz you handed in in class).  The new copy of the quiz (at the link above) has better instructions on what you can use or not use.  You can also email me for clarifications.
  • For this re-do, it is a violation of the honor code to work together, or use the help of a tutor or friend or any outside source, including the internet.  You can, however, use your course notes and textbook.  There is no time limit besides the deadline for hand-in, which is in class Monday.


  • We are reshuffling groups.  I am forming new groups using the survey you completed on Canvas about group preferences.  (If you didn’t complete the survey, you must have forgotten to read the website before Friday’s class.  You’ll be assigned to groups randomly in that case.)  The new groups will be formed on canvas and you can check them by logging in.  You can now log in to canvas to find your new groups.  You should also be able to contact one another there.

For Monday’s class:

  • Re-do your Proof Quiz #3 as described above if you desire (optional).
  • Contact your new groups to schedule a time for this week’s groupwork.
  • Please read Hammack, Sections 4.4 and 4.5, and do exercises 14-17 (compare with solutions to 15, 17 in the back).  This deals with the topic of “cases” and the use of the phrase “without loss of generality” (also known as WLOG).  These will come up naturally in future, but for now I’ll consider them covered by your reading in the book, at least in the sense that you are familiar with them, if not a master of them.
  • In class, we will work on negation and introduce truth tables.
  • There will be a badges quiz, and the available badges will be the same as last time.  A good goal for this quiz is to finish off any Sets badges you have not yet earned, and then focus on Proofs I if you have room for more.  For example, 70% of students have earned Sets I, and so I’ll probably stop including it in badges quizzes in a couple weeks (I will warn you before the last chance).  The Logic IV badge is material we will cover soon, but is still a bit “ahead” of where we are.