Dieudonne

The approximation theorem (detailed proof) #ALNT-LB 1.3.DP Chapter 1 Section 3 #Algebraic Number Theory # Lecture note Benois


Listen Later

Theorem 3.1 

Let ||-||_1, ..., ||-||_n be inequivalent norms on K, and let a_1, ..., a_n be arbitrary elements of K. Then for any epsilon>0, there exists a in K such that ||a-a_i||_i < epsilon. 

Lemma

Let ||-||_1, ..., ||-||_n be inequivalent norms on K, then there exists t in K such that ||t||_1>1 and ||t||_i < 1 for i in {2, ..., n}. 

Question:

1. Easy proof of the lemma for n=2 case?

2. A rigorous  proof that ||t^N/(1+t^N)|| tends to 1 when ||t||>1 ? (should use triangular inequality)

3. Relation of the theorem with the Chinese remainder theorem?

...more
View all episodesView all episodes
Download on the App Store

DieudonneBy Luc