CAS CS 131, Combinatoric Structures Spring 2012

Course Description

Representation, analysis, techniques, and principles for manipulation of basic combinatoric data structures used in computer science. Rigorous reasoning is emphasized. (Counts as a CS Background Course for the concentration.)


Basic (high school level) calculus and algebra.


Tues-Thur 2-3:30 pm, GCB 205.

I expect you to come to lectures (on time!) and I encourage you to participate. There is no perfect textbook for the class, and lectures are your important source of information. Be sure to take good notes.

Discussion Labs

Lab: MCS B29, Mon, 1:00pm-2:00pm
Lab: MCS B33, Mon, 2:00pm-3:00pm


Evimaria Terzi,
Office Hours: Tuesday 3:30 pm - 5:00 pm and Wed 9:30 am -11:00 am or by appointment.
Evimaria’s office: MCS280

Teaching Assistant

Behzad Golshan,

Office Hourse: Thursday 12:00 (noon) - 1:30pm and Fri 3:00pm - 4:30pm.
Behzad’s office hours take place in the undergraduate lab

The Teaching Fellow will lead the discussion sessions. The objective is to reinforce the concepts covered in the lectures, and answer questions (or provide clarifications) regarding the homework assignments.

The purpose of the office hours of the Instructor and Teaching Fellow is to answer specific questions or clarify specific issues. Office hours are not to be used to fill you in on a class you skipped or to explain entire topics. Please come to class and to your discussion session.


There is no perfect textbook that covers all the material of this course from a CS perspective. We will mostly make use of the following online notes. Do not print anything yet! The notes are 339 pages long, so you might consider printing them out in chapters as we get to them rather than all at once. We won’t cover all chapters anyway.

Notes for MIT’s CS 6.042 course (PDF format), by Eric Lehman and Tom Leighton, 2004.

Together with your lecture notes, these notes should be quite sufficient, but if for some reason you want to do additional reading, you might consider some discrete mathematics book, e.g., Discrete Mathematics and Its Applications, by Kenneth H. Rosen, McGraw Hill. However, be warned: each discrete math book has its cons and they can be quite expensive!

Grading Policy

Incompletes will not be given.

Late assignments will not be accepted. The assignment grade will be the average over all assignments (the two lowest-grade assignments will be ignored).

Mailing List

(Tentative) Schedule

Jan 17, 19 Introduction: Logic and Proofs Chapter 1
Jan 24, 26 Proof by Induction I Chapter 2
Jan 26 Homework 1; Due Feb 2 at 2pmpdf solutions
Jan 31, Feb 2 Proofs by Induction II Chapter 3
Feb 2 Homework 2; Due Feb 9 at 2pm pdf solutions
Feb 7 Review class
Feb 7 Review material for exam 1review-questions and solutions
Feb 9 Exam 1
Feb 14, 16 Sums and Approximations Chapters 10, 11
Feb 16 Homework 3; due Feb 23 pdf solutions
Feb 21 No Class; Monday Schedule
Feb 23 Recurrences Chapter 12
Feb 28, Mar 1 Recurrences Chapter 12
March 1 Homework 4; due March 8 pdf solutions
Mar 6,8 Recurrences Chapter 12, 13
Mar 8 Homework 5; due March 22 pdf solutions
Mar 13,15 Spring Break
March 20,22 Recurrences Master Theorem
Mar 22 Homework 6; due March 29 pdf solutions
Mar 23 Review material for exam 2review-questions andsolutions
Mar 27 Review Class
Mar 29 Exam II
April 3, 5 Counting Chapters 14, 15, 16
April 6 Homework 7; Due April 13 pdf solutions
Apr 10,12 Counting Chapters 14, 15, 16
April 13 Homework 8; Due April 23 pdfsolutions
Apr 17,19 Counting Chapters 14,15, 16
Apr 24, 26 Probability Chapters 18,19
April 26 Homework 9; Due May 3 pdf solutions
May 1 Review class
May 1 Review material pdfand solutions

Collaborations and Academic Honesty

Course participants must adhere to the CAS Academic Conduct Code. All instances of academic dishonesty will be reported to the academic conduct committee. Collaboration/Academic Honesty

I encourage you to discuss course material and even problem sets with other students in the class (esp. on the class mailing list), subject to the following rules:

I expect you to follow these rules as well as the academic conduct code of CAS/GRS. If you have any questions or are not sure what is appropriate, consult me before taking steps that you are afraid may violate the rules.

If you violate the academic conduct code, you will be reported to the Academic Conduct Committee.