Lecture 10

We covered most of Chapter 8 (functions and one-to-one). Specifically

• The concept of one-to-one, including two versions of the definition (one the contrapositive of the other).
• The pigeonhole principle.
• Sample pigeonhole and concrete one-to-one proofs.
• Proof that a strictly-increasing function is one-to-one.

We looked at another abstract claim involving one-to-one and onto: proof next class.

Announcements

• Midterm is Tueday, October 2nd, in class. Remember to bring a photo ID because we'll check them during the exam. (But if you realize you've forgotten yours, don't have a panic: there is a backup plan.)
• Midterm review materials are posted on the web site, plus two optional relations review quizzes on moodle.
• HW 3 solutions and HW 2 grades should appear later this week.
• The first honors homework is now available on our web site, due October 12th.
• WCS office hours: Monday-Thursday, 2-3pm, room 1318 Siebel.