Math 103B Spring 2023 Sections B



Calendar

Week Monday Wednesday Friday
1

Group Actions, Orbits, Stabilizers

Ch 14.1. Make sure you understand Theorem 14.11. Ch 5.4 Q32b.

Class Equations (counting with orbits and stabilizers), Conjugacy Class

Ch 14.2 (you can skip Corollary 14.16).

Rings

Ch 16.1, up to Prop 16.8. Give exmaples and counter-examples to each object in Figure 16.1. Also make sure you know what a zero divisor is.

2

Integral Domains and Fields

Ch 16.2. Reading question 2,3. Ch 16.7 Q3ad.

Check 1; Ring homomorphisms and Ideals

Ch 16.3, up to Remark 16.28. Prop 16.27 is important, so you have to read the proof. Ch 16.7 Q6.

Quotient Rings, Isomorphism Theorems

Ch 16.3, Thm 16.29 - end. Read the proof for 16.30. Focus on Theorems 16.30, 16.31 and 16.34.

3

Maximal and Prime Ideals

Ch 16.4. Pay attention to 16.35 and 16.38, which are super important. Ch 16.7 Q4a

Check 2; Chinese Remainder Theorem

Ch 16.5, up to Example 16.44. Focus on the examples.

Polynomial Rings

Ch 17.1. Theorem 17.5 is super important.

4 Catch-up / Review Midterm 1 Solution

Division Algorithm, Euclidean Algorithm

Ch 17.2. Work on Ch 17.5 Q3a, 4a.

5

Irreducible Polynomials

Ch 17.3. Make sure you understand Theorem 17.14 and 17.17.

Check 3; Field of Fractions

Ch 18.1. Make sure you understand 18.5 - 18.7.

UFD and PID

Ch 18.2, up to Example 18.17. What is an example of a non-PID?

6

Polynomial Rings over Integral Domains

Ch 18.2, ''Factorization in D[x]'' to end. Focus on ''primitive''. Give an example of a primitive polynomial, and a non-primitive polynomial, both in Z[x].

Check 4; Field extensions

Ch 21.1, up to Example 21.6. Focus on examples.

Algebraic extensions

Ch 21.1, from ''Algebraic elements'' up to Theorem 21.9.

7 Catch-up / Review Midterm 2 Solution

Minimal Polynomial

Ch 21.1, from Theorem 21.10 to Example 21.14. Make sure to understand Examples 21.11 and 21.14.

8

Finite extensions

Ch 21.1, from right after Example 21.14 to Theorem 21.22. Focus on Examples 21.20 and 21.21.

Check 5; Algebraic Closures

Ch 21.1, ''Algebraic Closures''. The most important part from this section is to understand the statement ''C is algebraically closed''.

Splitting Fields

Ch 21.2. Make sure to understand why Example 21.29 is a splitting field, but Exmaple 21.30 is not. You can skip Lemma 21.32 and Theorem 21.34, but you should read the statement of 21.36.

9 Memorial

Check 6; Finite Fields

Ch 22.1. Make sure to understand Examples 22.8 and 22.13. Also pay attention to the statement of 22.1, 22.2, 22.5, 22.6, 22.10.

Field Automorphisms

Ch 23.1, up to Example 23.11. Focus on the examples.

WARNING: The book calls the group ''Galois group'', denoted by G(E/F). In most other literature, this is NOT the Galois group. Instead, it is called ''Automorphism gropu of E over F'', denoted Aut(E/F). We will use this Aut(E/F) notation. The notion ''Galois group'' is reserved for next week, when the extension is Galois.

10

Separable extensions

Ch 23.1, ''Separable Extensions''. Also re-read Lemma 22.5 from Ch 22.1.

Check 7; Normal extensions

Ch 23.2, up to Figure 23.22. Give an example of a normal extension and a non-normal extension of Q.

Fundamental Theorem of Galois Theory

Ch 23.2, from Thm 23.23 to end. Make sure to understand Example 23.25.

11

Final Exam: Jun 14 (Wed), 3-5pm (duration tentative)