CAS CS 131: Combinatoric StucturesFall 2022Official DescriptionRepresentation, analysis, techniques, and principles for manipulation of basic combinatoric structures usedin computer science. Rigorous reasoning is emphasized.PrerequisitesNone.Staff and Office HoursInstructors: Peter B. Golbus and Leo ReyzinHead Teaching Fellow: Tim JackmanTeaching Assistants: Jonas Raedler and Joy ShenCourse Assistants: Dhruv Chandwan, Jared Chou, Evan Denenberg, William Huang, Maria Kharchenko,Jiawei Sun, Shuo Wang, Gregorio Yang, Jolene Yu, Tiffany YuOffice hours: there will be about 20 total office hours held each week by all the course staff. The hoursmay change somewhat from week to week. They will be posted via Piazza (see below).Communication and All Questions: PiazzaMaterials (including HW assignments), Q&A (including questions to the professors), class announcements,and other communcation will be handled via Piazza (piazza.com; apps for mobile devices also available).Use this link https://piazza.com/bu/fall2022/cascs131 to sign up with Piazza ASAP, using your BUemail address. Piazza has different notification options; choose one that works for you (“I didn’t get / seethe announcement” is not an acceptable excuse).Piazza is the place to post and answer HW questions; even though anonymous posts are allowed, theyare strongly discouraged: you need to get to know your classmates, and it’s hard to do so when no one knowsyour name.Please do not send course staff individual email: class-related but nonpublic questions should goto private posts on Piazza rather than to email. Email will get easily lost in overcrowded inboxes.LecturesThe lecture is in SAR (635 Commonwealth Ave) room 101, Mondays, Wednesdays, and Fridays, 2:30–3:20(A1) and 3:35–4:25 (B1).We expect you to come to lecture and encourage you to participate. We will try to keep the class interactive.Lectures are your primary source of information. Usually readings will be available, but not always; moreover,even when available, they won’t always match the style of lecture. They cannot substitute for coming tolecture. The whole point of getting your education on a bricks-and-mortar campus is the ability to interact—take advantage of it.We will endeavor to record lectures in case you have to miss them due to illness or other emergencies,but the technology does not always cooperate. Unfortunately, recording quality is generally mediocre due toequipment limitations. Recordings will be available via Piazza (see above).1In-Lecture Work on Top Hat: 5% of your gradeWe will be taking attendance and assigning quick problems by using Top Hat, an interactive in-lecture Q&Asystem. During lecture, you will be accessing Top Hat from your web browser or via a mobile app (if youwant the latter option, please install it ahead of the first class); you must sign in using your BU credentials athttps://app.tophat.com/e/224199 for the A1 (2:30pm) lecture and https://app.tophat.com/e/116716for the B1 (3:35pm) lecture.You will need a functional device to use Top Hat in class. There is no way to make up Top Hat workafter class. However, a grade above 80% on Top Hat will be rounded to 100% at the end of the semester,to allow for classes missed due to illness. Therefore, please do not ask about missed Top Hat points unlessyou are missing more than two weeks of classes for a justifiable reason. However, please do not attend classif you are contagious — being sick for more than two weeks is a justifiable reason for missing work, and wewill work with you in such a circumstance.Top Hat Pro, which is required for this class, costs you $30 for the semester, regardless of how manyclasses use it. Do not pay for any add-ons. If you are expecting to use it again in Spring or Summer 2023(CS 111,132, 210, 237, and 330 are likely to use it), you can save a bit by buying a year-long subscription for$48 instead of two semester-long subscriptions for $30 each. In case of technical issues with Top Hat, theyhave tech support available at https://success.tophat.com/s/contact-main.Readings and zyBooks Assignments: 5% of your grade.Our readings will come mostly from an on-line textbook. Create an account at http://learn.zybooks.com.You should see a “my library” page once you log in; there, enter the following code in the search box:BUCS131ReyzinFall2022. It should cost $58 to purchase access to the book; subscriptions will last untilJanuary 7, 2023. If you have problems with zyBooks, please contact [email protected] every assigned reading, you will be required to complete participation and challenge activities directlyin zyBooks. These will be due before lecture. They will be worth 5% of your final course grade. LatezyBooks activities will not be accepted, because the whole point of these assignments is for you to be preparedfor class. A grade above 80% on zyBooks will be rounded to 100% at the end of class, to allow for workmissed due to emergencies. Therefore, please do not ask about missed zyBooks points unless you are missingmore than two weeks of classes for a justifiable reason.Problem Sets and Labs: 40% of your gradeThere will be (roughly weekly, about 10 total) problem sets, containing mostly written problems and oc-casional programming exercises to be handed in electronically via gradescope (we’ll provide submissioninstructions on the first assignment). They will be typically due on Mondays at 11:59pm, but see eachproblem set for details.To get you started with each week’s homework, the Tuesday or Wednesday lab (you should be signed upfor one; it doesn’t matter if it’s an A section lab or a B section lab) will guide you through similar problems.Late homework will be typically accepted until Wednesday at 2:00pm, for a 15% penalty (i.e., you willbe graded as usual and then your grade will be multiplied by 0.85), but see each problem set for details.We will not provide extensions beyond that, not because we are unsympathetic to your time pressures,but because we need to be able to post solutions and discuss the problems in lecture. Delaying the postingof solutions for all 300 people in the class in order to accommodate the needs of a few is not an acceptableoption.We understand, however, that sometimes circumstances are beyond your control. For just such anoccasion, we will replace the lowest homework grade with the maximum of your final exam grade and theaverage of the remaining homework grades. This will happen automatically when we assign