Skip to main content
2 of 2
deleted 7 characters in body; edited tags
Rahman. M
  • 2.4k
  • 2
  • 24
  • 42

Automorphisms of vector spaces and the complex numbers without choice

In Zermelo-Fraenkel set theory without the Axiom of Choice (AC), it is consistent to say that there are models in which:

  1. there are vector spaces without a basis;
  2. the field of complex numbers $\mathbb{C}$ only has two automorphisms (identity and complex conjugation).

Before I even ask my main question, I want to ask two "pre-questions" (as I am not a logician):

  • is my formulation "in Zermelo-Fraenkel set theory without the Axiom of Choice (AC), it is consistent to say that there are models in which ..." formally correct? (And if not, what is a formal correct statement ?);
  • for the second statement above, what is a precise reference in which I can find this statement?

Now for my main question: is it also true that it is consistent to say that there are models of ZF set theory without AC, in which every vector space over $\mathbb{C}$ has a base (or even stronger: in which dimension is well defined), and in which $\mathbb{C}$ also has precisely two field automorphisms?

THC
  • 4.5k
  • 21
  • 33