MAT 312 / AMS 351 (Applied Algebra) - Fall 2026

Time and place: TuTh 3:30-4:50 p.m.; Library W4550

Instructor: Radu Laza

Office: Math Tower 4-121
Email: radu.laza@stonybrook.edu
Office hours: Tue 5:00-6:15 p.m.; Thu 2:15-3:15 p.m.

TAs: Connor Lehmacher (Recitations 1 and 3) and Zhulei Pan (Recitation 2)

Overview

This course is an introduction to abstract algebra, focusing on groups, rings, homomorphisms, and related algebraic concepts. Alongside the theoretical foundations, the course has a strong applied component, with particular emphasis on public-key cryptography and error-correcting codes. Other topics and applications may include informal set theory, relations, the Chinese remainder theorem, Burnside's theorem, and computational complexity. This course is offered as both AMS 351 and MAT 312.

Prerequisite: AMS 210 or MAT 211.

Textbook: Humphreys and Prest, Numbers, Groups and Codes , 2nd edition.

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Grading


Schedule

Week Topic Sections Covered HW Assignments
(1) Aug 25, 27 Euclidean algorithm and gcd 1.1
(2) Sept 1, 3 Primes and unique factorization

Congruence classes
1.3

1.4
HW1 (due the week of Sept 7)
(3) Sept 8, 10 Solving linear congruences

Euler's theorem; Public-key cryptography
1.5

1.6
HW2 (due the week of Sept 14)
(4) Sept 15, 17 Permutations

Sign of a permutation
4.1

4.2
HW3 (due the week of Sept 21)
(5) Sept 22, 24 More on permutations

Review


Chapter 1, Sections 4.1-4.2
(6) Sept 29, Oct 1 Midterm 1: Tuesday, Sept 29 (in class)

Introduction to groups
Chapter 1, Sections 4.1-4.2

4.3
HW4 (due the week of Oct 5)
(7) Oct 6, 8 Algebraic structures

Subgroups
4.4

5.1
HW5 (due the week of Oct 19)
(8) Oct 13, 15 No class

Cosets and Lagrange's theorem


5.2
HW6 (due the week of Oct 26)
(9) Oct 20, 22 Normal subgroups and quotient groups

Groups and error-correcting codes
5.3

5.4
HW7 (due the week of Nov 2)
(10) Oct 27, 29 Review

Midterm 2: Thursday, Oct 29 (in class)
Sections 4.3-4.4, Chapter 5

Sections 4.3-4.4, Chapter 5
(11) Nov 3, 5 Polynomials 6.1, 6.2 HW8 (due the week of Nov 9)
(12) Nov 10, 12 Irreducible polynomials and factorization 6.3 HW9 (due the week of Nov 16)
(13) Nov 17, 19 Polynomial congruence classes 6.4
(14) Nov 24, 26 Cyclic codes

No class - Thanksgiving
6.5

HW10 (due the week of Nov 30)
(15) Dec 1, 3 Review

Final Exam: Thursday, Dec 3 (in class)
Discussion of sample final

Cumulative