Math 448: Modern Algebra I

Assignment #4 – Due Tuesday, Sep 15, 2026
  1. Prove the theorems in this Lurch document. Save it in your Dropbox folder in a subfolder named assignment 04 (lower case, one space, a zero before the 3, no # or hyphens). No AI or Google! Yuk! 🤮
  2. Putnam Training! (optional bonus points) Look at the problems in Round 1 of this year’s USAMTS competition. We will follow the same rules and regulations of the competition itself, but you will only submit any solutions you find to me, not to the contest (since you aren’t eligible!). Solutions should be handed in a folder named USAMTS Round 1 in your Dropbox folder before 10pm Eastern on October 13, 2026. You don’t need to verify them in Lurch, but you should write up your solutions either in Lurch or LaTeX. Game on!

Course Handouts and References

  • Lecture Notes – check here often for revised lecture notes for our course
  • Course Syllabus
  • Proofs – notes and Lurch contexts from my Math 299 course on mathematical proofs

Software and Handouts

  • Lurch – a math word processor that can check your proofs!
  • Overleaf – a free website where you can easily produce LaTeX math documents through a web browser
  • Toy Proofs – a “toy” proof system I developed to introduce students to the concept of formal proofs.
  • Group Explorer – amazing group visualization and exploration software from Nathan Carter

Homework Assignment Template

Putnam!
Tentative Schedule
#DateTopic
1 Tue, Sep 1 Introduction; Logic and Proof
2 Thu, Sep 3 Appendix B,C,D (equivalence relations & induction)
3 Tue, Sep 4 Section 1.1: Division Algorithm
4 Thu, Sep 10 Section 1.2: Divisibility
5 Tue, Sep 15 Section 1.3: Primes and Unique Factorization
6 Thu, Sep 17 Section 2.1-2.2: Congruence and Modular Arithmetic
7 Tue, Sep 22 Section 2.3: $\mathbb{Z}_p$ when $p$ is prime
8 Thu, Sep 24 Section 3.1: Rings
9-10 Tue, Sep 29 Section 3.2: Basic Properties of Rings
11 Thu, Oct 1 Section 3.3: Isomorphism and Homomorphism
12 Tue, Oct 6 Section 4.1: Polynomials and Division Algorithm
13 Thu, Oct 8 Section 4.2: Divisibility in $F[x]$
14 Thu, Oct 15 Section 4.3: Irreducibles and Unique Factorization
15 Tue, Oct 20 Section 4.4: Polynomial Functions, Roots, and Divisibility
16 Thu, Oct 22 Section 5.1: Congruence in $F[x]$
17 Tue, Oct 27 Section 5.2: Modular Arithmetic in $F[x]$
18 Thu, Oct 29 Section 5.3: $F[x]\left/p(x)\right.$ when $p(x)$ is Irreducible
19 Tue, Nov 3 Section 6.1: Ideals and Congruence
20 Thu, Nov 5 Section 6.2: Quotient Rings and Homomorphisms
21 Tue, Nov 10 Section 7.1: Groups
22 Thu, Nov 12 Section 7.2: Basic Properties of Groups
23 Tue, Nov 17 Section 7.3: Subgroups
24 Thu, Nov 19 Section 7.4: Isomorphisms and Homomorphisms
25 Tue, Nov 24 Section 8.1: Congruence and Lagrange’s Theorem
26 Tue, Dec 1 Section 7.5: Symmetric and Alternating Groups
27 Thu, Dec 3
28 Tue, Dec 8
29 Thu, Dec 10