General Information | Course Description | Grading | Piazza | Homework | Course Conduct | Accommodations

General Information

TR 1:25pm–2:40pm, Hollister Hall B14, map

  • Eshan Chattopadhyay, Gates Hall 319, email
    office hour: TBD
  • Course Description

    In this course, we explore the power and limitations of efficient algorithms. We compare basic models of computations such as Turing machines and Boolean circuits. The course illustrates the notion of computational intractability through the concept NP-completeness and the computational foundations of modern cryptography, the role of randomness in computation and approximation in the modern theory of computing.


    The direct prerequisite for this course is CS 4820. We will also assume that everyone is familiar with the material in CS 2110, CS 3110, and CS 2800 — direct and indirect prerequisites of CS 4820. Concretely, you should remember your basic algorithms (e.g., dynamic programming and network flow), basic computability (e.g., Turing machines and undecidability of the halting problem), and basic NP-completeness. We expect everyone to be comfortable reading and writing mathematical proofs at the level of CS 4820.

    Course Material

    Introduction to Theory of Computation Computational Complexity: A Modern Approach The textbook for the course is Computational Complexity: A Modern Approach by Sanjeev Arora and Boaz Barak. (For this book, drafts of all chapters are available here.) The book Introduction to Theory of Computation (3rd edition) by Michael Sipser can be used as a reference for some topics in this course.


    Your grade will based on weekly homework, participation (based on class participation, participation on Piazza, and completion of a course evaluation), two prelims (in class) , and one final exam. Each of these components will be given the following weights:

    • homework: 75%
    • participation: 5%
    • prelim 1: 20%


    We will be using Piazza as an online discussion forum. Piazza allows for open discussions of all course-related questions. You are encouraged to post any questions you might have about the course material. The course staff monitor Piazza closely and you will usually get a quick response. If you know the answer to a question, you are encouraged to post it. Posting questions or answers that are endorsed by TAs or instructors can improve your participation grade.

    By default, your posts are visible to the course staff and other students, and you should prefer this mode so that others can benefit from your question and the answer. However, you can post privately so that only the course staff can see your question, and you should do so if your post might reveal information about a solution to a homework problem. You can also post anonymously if you wish. If you post privately, we reserve the right to make your question public if we think the class will benefit.

    Everyone who preregistered for the course will be signed up automatically by the start of the course. If you have never used Piazza before, or if you did not preregister for the course, visit the Piazza CS 4814 page to sign up.

    Piazza is the most effective way to communicate with course staff. Please avoid email if Piazza will do. Broadcast messages from the course staff to students will be sent using Piazza and all course announcements will be posted there and pinned, so check the pinned announcements often!


    Homework is an important part of the course. We will have weekly homework assignments. All homework assignments will be posted on CMS. Most homework assignments will be due on Thursday at 11:59pm.


    We will require problem sets to be typeset and submitted as a PDF. This requirement is for everyone's benefit. In general, we recommend that you first develop your solutions in draft form, and then write or type your solution in a concise way. Typesetting not only makes the last step essential (instead of handing in solution in draft form), it also makes it much easier for you to edit and improve your writeup, as well as easier for your TAs to read your proofs. It is up to you which tool you use; though we recommend LaTeX, tools like the Equation Editor in Microsoft Word can be surprisingly effective as an alternative. See typesetting resources for a list of typesetting software and references.

    For some proofs or writeups, it may be helpful to use a figure to explain your thinking more concisely. This is encouraged! Again, it is up to you how you want to include that in your writeup, whether it is a picture of a drawing in your notebook that you took with your phone or something you made digitally, as long as the figure was produced by you personally and is clear enough to see, it's a great idea to include it.

    Late Submissions

    You have six late days. Grades from a late submission count only if you have late days left. You can use at most three late days per homework. The purpose of late days is to help handle unforseen circumstances such as illness, interviews, or conflicting deadlines that may prevent you from turning in your assignment on time. If an emergency situation arises for which late days will not be sufficient accommodation, contact an instructor as soon as possible.


    In the real world of research, collaboration and conversation is an important part of how ideas get generated. So too in this course; we encourage you to discuss with your peers in the course to brainstorm ideas for how to get through homework. However, your solution must be written up completely on your own; you are not allowed to share digital or written notes or images of your work in any form with each other. Just like in research, your work must also include acknowledgements of all students with whom you collaborated. Both the physical or digital distribution of information about solutions and the failure to acknowledge collaborators are serious violations of academic integrity.

    Admissible Resources

    For the homework, it is not admissible to use resources beyond course material and student discussions. In particular, you may not use Wikipedia, or search the Web, or look at any textbook, other than the ones assigned/recommended in the course. Using such additional resources is a violation of academic integrity. If you feel the resources available to you are insufficient, talk to course staff or ask questions on Piazza.

    Advice for Success

    The assignments can often require creative insights and complex proofs beyond what previous courses have required. Here are a few tips for succeeding in your writeups:
    • Start your assignments early. Even if you aren't writing anything down yet, looking over the problem set well in advance of the due date can ensure you have enough time to brainstorm possible solutions and to clear up confusion about how to interpret a problem. Creativity doesn't work well on a deadline.
    • Talk with classmates at a similar level about ideas. As previously stated, while you cannot share physical or digital solutions of any kind to these problems, we actively encourage you to talk to classmates while you work through them. In particular, we recommend finding a group of students to meet with throughout the semester in advance of the deadline to talk about ideas. For best results, make sure those students are at the same level of understanding of the material as you; talking through your ideas with colleagues with a similar level of understanding will make talking through ideas with each other easier and more equitable, and is more likely to leave you prepared for course exams.
    • Ask questions in class, in office hours, and on Piazza. The material in this class moves quickly and is often cumulative. If you find yourself scratching your head after a lecture, even after consulting the textbook and course notes, you're certainly not alone, and it's better to seek help then than to wait until you are more confused.

    Course Material Copyright

    Course materials posted on this website, piazza, or CMS, are intellectual property belonging to the author. Students are not permitted to buy or sell any course materials without the express permission of the instructor. Such unauthorized behavior constitutes academic misconduct.

    Course Conduct

    We understand that our members represent a rich variety of backgrounds and perspectives. Cornell University is committed to providing an atmosphere for learning that respects diversity. We expect students to communicate in a respectful manner with the instructors, course staff, and fellow students, in a way the honors the unique experiences, values, and beliefs represented by different members of our community.

    Academic Integrity

    Any violation of academic integrity will be severely penalized. You are allowed to collaborate on the homework to the extent of formulating ideas as a group. However, you are expected to write up (and understand) the homework on your own, and you should acknowledge the names of the students with whom you collaborated.

    From Cornell's code of academic integrity:

    Absolute integrity is expected of every Cornell student in all academic undertakings. Integrity entails a firm adherence to a set of values, and the values most essential to an academic community are grounded on the concept of honesty with respect to the intellectual efforts of oneself and others. Academic integrity is expected not only in formal coursework situations, but in all University relationships and interactions connected to the educational process, including the use of University resources. […]

    A Cornell student's submission of work for academic credit indicates that the work is the student's own. All outside assistance should be acknowledged, and the student's academic position truthfully reported at all times. In addition, Cornell students have a right to expect academic integrity from each of their peers.


    This course complies with the Cornell University policy and equal access laws to ensure that students with disabilities can still participate fully in this course. Requests for academic accommodations should be made during the first three weeks of the semester, except for unusual circumstances, so arrangements can be made as soon as possible. Students are encouraged to register with Student Disability Services, as we may require verification of eligibility to provide appropriate accommodations.