Math 55 - Discrete Mathematics - Fall 2011

Lectures: Tuesday and Thursday, 3:30-5:00pm, 100 Lewis

Professor: L. Williams (office 913 Evans, e-mail

Office Hours: Monday 4:00-5:00pm, Tuesday 5:00-6:30pm, or by appointment.

Teaching assistants:

Course control number: 54182

For extra help: check out the Student Learning Center. Their study group meets TTh 1-2, room 201A.

Final Exam: Friday, December 16, 7-10pm, in 155 Dwinelle.

Course description

This course provides an introduction to logic and proof techniques, basics of set theory, elementary number theory and cryptography, combinatorial enumeration, discrete probability, and graph theory, with a view towards applications. It is designed for majors in mathematics, computer science, statistics, and other related science and engineering disciplines.


Required text: information can be found here. This is a custom edition of the 7th edition of the textbook Discrete Mathematics and its Applications, by Kenneth H. Rosen, McGraw-Hill. (More specifically, it is identical to the 7th edition except a few chapters are missing; as a result, it is somewhat less expensive than the full-length version.)

Some students have asked me if they can use the 6th edition of the textbook instead. The 6th and 7th editions of Rosen are quite similar, but the order of presentation of topics is slightly different. I will be assigning a number of problems out of the book, so if you have the 6th edition of the textbook, you'll have to look at the 7th edition in order to find out what problems to do.

Problem Sets

Homework will be assigned weekly. About twenty problems covering the lecture material of each week will be due at the beginning of your section on Wednesday of the following week. No late homework can be accepted. Your TA will verify that you are working the assigned problems, but only one of the problems (marked after the due date by a star) is fully graded. Homework solutions will be posted below on the respective due date.

All solutions that you submit must be your own work and must not be copied from somewhere else. A solution that is blatantly copied from another source will receive zero credit. There will be serious consequences for repeat offenders.


There will be two in-class midterms, on Tuesday, October 4, and on Thursday, November 17. A review session will be held during the class preceding the midterm. *No books, notes, calculators, scratch paper or collaboration are permitted at any exam*. Your student photo ID is required at the midterms and final exam. No make-up midterms will be given; instead, missing midterm scores will be overridden by the final exam score.


The final exam will be on Friday, December 16, 7-10pm. Note that there are no makeups for the final exam, so you must plan your holiday travels accordingly.


Homework 15%, Midterms 25% each, Final 35%. Your lowest two homework scores will be dropped, and the final exam score will override any lower midterm score. This means that, a posteriori, your final exam may count as 60% or 85% instead of 35%. Incomplete grades are rarely given, and only for a documented serious medical problem or genuine personal/family emergency, provided you have a C average on the previous coursework.