Field and Galois· L03
Galois groups & correspondence
Compositum, Gal(L/K), fixed fields, and the Galois correspondence.
Canonical content
Galois groups, fixed fields, and the correspondence live on the Notes pages (III–IV). Legacy HTML under /legacy/galois/ is backup only.
What you will cover
Compositum of extensions, , fixed fields, Dedekind–Artin, and when is Galois.
Visualization
Field Extensions III — compositum & Gal
Compositum · Galois group · fixed fields · correspondence preview.
Visualization
Field Extensions IV — Galois & normal
Galois criterion · Dedekind–Artin · Aut(ℚ), Aut(ℝ) · normal / splitting-field exercises (1.80–1.88).