This has H = 2, V = ...; ex. II.4.1 can be applied.
Say is determined by .
- Replace with and use II.4.1 to reduce to the case injective.
- Show there are injections where the last is the integral closure (in the fraction field of B).
- use 4.11A to reduce this to for all valuation rings (of ) containing
- use the valuation ring criterion of properness.