Mainpage Syllabus Homework Notes

Syllabus for 21-301

  • Course Outline:

    We will cover chapters in "A Course in Combinatorics", second edition, by van Lint and Wilson that are of mutual interest to the students and course staff. We'll begin with a brisk review of chapters 1-4, and then move on to cover chapters 5-7 in more depth. I currently favor covering chapters 10, 13-23, 25, 29, 31-33 and 35, but will take into account evolving taste in the material on the part of students and course staff.

  • Classes:

    21-301 meets MWF from 2:00 to 2:50 MWF in Baker A51.

    Our wonderful Course Staff will also hold office hours and review sessions.

  • Office:

    Gates 4005
  • Phone:

  • Email:
  • Course Website:
  • Office Hours:

    Monday from 12:30-1:30, Wednesday from 12:20-1:40, and by appointment.
  • Course Staff Office Hours:

    Course Staff Office Hours
  • Help:

    In addition to class, review sessions, and office hours, individualized tutoring and other help options are available through Academic Development.

  • Homework:

    Homework exercises are an essential part of the course. It is difficult to understand the material and do well on the exams without working through the homework problems in a thoughtful manner. Discussion of the homework with your peers is encouraged, but copying any part of another person's homework is not permitted. Please think about the problems posed, your strategies, and the validity of your logic and explanations.

    Homework is to be submitted through Gradescope by the required due date and time. Homework that is submitted after the due date and time, but before the solutions are posted will receive half credit (with an asterisk to get full credit if the course grade is borderline). If you choose to handwrite and then scan homeworks, then here is a helpful resource for scanning documents on campus: Scanning documents

    Homework and Exam regrade requests must be submitted within one week of the return date.

  • Textbook:

    We will use "A Course in Combinatorics", second edition, paperback, by van Lint and Wilson.

    Here are links to the pages of the textbook's first section: 1 2 3 4 5 6 7 8 9 10 11

  • Midterms:

    There will be two in-class midterm exams and a cumulative final exam. The dates of the midterm exams are as follows:

    • Midterm 1:

      Wednesday, February 22
    • Midterm 2:

      Monday, April 10
  • Calculators:

    Calculators and and other electronic devices will not be allowed during the exams.
  • Grading:

    Your course grade will be determined as follows:

    • Each of the two midterm scores: 20%
    • Homework: 30%
    • Final Exam: 30%

    The highest possible grade cutoffs will be 90% for an A, 80% for a B, 70% for a C, and 60% for a D. These cutoffs may be lowered slightly, but will not be increased.

  • Learning Objectives

    Apply the logical structure of proofs and work with definitions to produce logically valid, correct and clear arguments.

    Work with abstract and concretely defined combinatorial objects; in particular with graphs, posets, networks and codes.

    Construct direct and indirect proofs, proofs by induction, and proofs by contradiction, and determine which type of proof is most useful in a given situation. Analyze and critique proofs with respect to logic and correctness.

    Interpret abstract definitions, create examples to aid intuitive understanding of abstract definitions, to provide counterexamples, and to formulate and prove conjectures.

    Apply basic combinatorial principles to count the number of elements in various sets, establish formulas by counting in two ways, and establish bijections between sets of equal cardinality.

    Determine equivalence relations on sets and equivalence classes, with applicability to combinatorics and discrete mathematics.

    Write solutions to mathematical problems and proofs of theorems that meet rigorous standards based on, organization, coherence, logical correctness, argument and support.

  • Wellness

    Take care of yourself. Do your best to maintain a healthy lifestyle this semester by eating well, exercising, avoiding drugs and alcohol, getting enough sleep and taking some time to relax. This will help you achieve your goals and cope with stress.

    All of us benefit from support during times of struggle. You are not alone. There are many helpful resources available on campus and an important part of the college experience is learning how to ask for help. Asking for support sooner rather than later is often helpful.

    If you or anyone you know experiences any academic stress, difficult life events, or feelings like anxiety or depression, we strongly encourage you to seek support. Counseling and Psychological Services (CaPS) is here to help: call 412-268-2922 and visit their website at Consider reaching out to a friend, faculty or family member you trust for help getting connected to the support that can help.

    If you or someone you know is feeling suicidal or in danger of self-harm, call someone immediately, day or night:

    • CaPS: 412-268-2922
    • Re:solve Crisis Network: 888-796-8226

    If the situation is life threatening, call the police:

    • On campus: CMU Police: 412-268-2323
    • Off campus: 911

    If you have questions about this or your coursework, please let me know.

  • Final Examination:

    Scheduled by the Registrar