Unit · year 3
MU-303 · Rings, Fields & Galois Theory
Threads structure26 lectures6 theorems
From factorisation in rings to the symmetry theory that settles the quintic.
PREREQUISITES
Lectures
| L01 | Rings: Axioms and Examples — |
| L02 | Ideals and Quotient Rings — |
| L03 | Ring Homomorphisms and the Isomorphism Theorems — |
| L04 | Integral Domains and Fields — |
| L05 | Polynomial Rings — |
| L06 | Divisibility, Primes, and Irreducibles — |
| L07 | Euclidean Domains |
| L08 | Principal Ideal Domains |
| L09 | Unique Factorisation Domains |
| L10 | Every PID Is a UFD |
| L11 | Gauss's Lemma and ℤ[x] |
| L12 | Tests for Irreducibility |
| L13 | Eisenstein's Criterion |
| L14 | Field Extensions and Degree |
| L15 | The Tower Law |
| L16 | Algebraic and Transcendental Elements |
| L17 | Splitting Fields — |
| L18 | Ruler-and-Compass Constructions |
| L19 | Finite Fields |
| L20 | Classification of Finite Fields |
| L21 | Separability and Normality — |
| L22 | The Galois Group |
| L23 | The Galois Correspondence |
| L24 | Solvability by Radicals |
| L25 | Insolvability of the Quintic |
| L26 | Synthesis: Symmetry Decides Solvability |
Theorems in this unit
T-089
Every PID is a UFD
Principal ideal domains have unique factorisation.
T-090
Eisenstein's criterion
A prime-based test for irreducibility of polynomials.
T-091
The tower law
Degrees of field extensions multiply.
T-092
The fundamental theorem of Galois theory
Subfields correspond to subgroups of the Galois group.
T-093
Classification of finite fields
There is exactly one field of each prime-power order.
T-094
Insolvability of the quintic
No general radical formula solves degree-five equations.