Discrete Mathematics
Fall 2026
EN.553.171 at Johns Hopkins: logic, proofs, number theory, counting and graph theory.
Syllabus
(PDF)
Lecture notes
(OneNote, written in class)
Exam information
what each exam covers, how to study and how exams are graded.
Office hours
You never need a reason to come to office hours. You don’t have to be stuck, and you don’t need a question prepared: come to work, to ask something small, or just to say hello. We’d love to see you there.
The instructor holds office hours three afternoons a week, and the TA team holds evening office hours three nights a week, in person and on Zoom.
Making the most of office hours
- Come as a group and bring your homework. The best use of this time is working through problems together and getting your questions sorted out before you submit.
- The TA office hours room is meant to be a shared space where you can settle in, work and collaborate.
- Students attending in person are helped first. Zoom is there as a backup for anyone who genuinely can’t make it to campus.
Exam schedule
Midterm 1
Oct 5
Midterm 2
Nov 4
Midterm 3
Dec 11
Final
Dec 21
Each exam has its own section on the exam information page. Practice 1 for each exam is released 10 days before that exam; Practice 2 is released at noon on the Thursday before it, in time for that day’s discussion section.
Weekly schedule
| Week | Dates | Topics | Notes |
|---|---|---|---|
| 1 | Aug 31 to Sep 4 | Introduction; Logic; Quantifiers | HW 0 due Thu |
| 2 | Sep 7 to 11 | Direct Proofs; Inequalities; Proof by Cases | No class Mon; HW 1 due Thu |
| 3 | Sep 14 to 18 | Set Theory | HW 2 due Thu |
| 4 | Sep 21 to 25 | Relations | HW 3 due Thu |
| 5 | Sep 28 to Oct 2 | Number Theory; Modular Arithmetic | HW 4 due Thu |
| 6 | Oct 5 to 9 | Multiplicative Inverses | Exam 1 (Mon) |
| 7 | Oct 12 to 16 | Diffie-Hellman Key Exchange; RSA | HW 5 due Thu |
| 8 | Oct 19 to 23 | Proof by Contradiction | Fall Break Thu and Fri (no class); HW 6 due Wed |
| 9 | Oct 26 to 30 | Counting | HW 7 due Thu |
| 10 | Nov 2 to 6 | Stars and Bars | Exam 2 (Wed) |
| 11 | Nov 9 to 13 | Combinatorial Proofs; Mathematical Induction | HW 8 due Thu |
| 12 | Nov 16 to 20 | Introduction to Graphs; Graph Induction | HW 9 due Thu |
| Nov 23 to 27 | Fall Recess | No class | |
| 13 | Nov 30 to Dec 4 | Planarity; Six Color Theorem | HW 10 due Thu |
| 14 | Dec 7 to 11 | Euler Characteristic | Exam 3 (Fri); HW 11 due Wed |
The schedule above is tentative and subject to change.
Reference books
- Edward R. Scheinerman, Mathematics: A Discrete Introduction.
- Oscar Levin, Discrete Mathematics: An Open Introduction, 4th edition.
- Clive Newstead, An Infinite Descent into Pure Mathematics.
- Mikhail Lavrov, Start Doing Graph Theory.