Part V
Ramification Theory

p=𝔭1𝔭2 in ℤ[i] if and only if p=x2+y2.

We will consider L∕K extension of algebraic number fields with [L:K]=n.

12 Different and discriminant
13 Unramified and totally ramified extensions of local fields
13.1 Structure of Units
14 Higher Ramification Groups