5:23 AM
163
It is well-known that it is consistent with $ZF$ that the only automorphisms of the complex field $\mathbb{C}$ are the identity map and complex conjugation. For example, we have that $\vert\operatorname{Aut}(\mathbb{C})| = 2$ in $L(\mathbb{R})$. But suppose that we are given a nonprincipal ultraf...
14
Simon Thomas asked in Ultrafilters and automorphisms of the complex field whether the existence of non-principal ultrafilters (over the natural numbers) suffices to imply the existence of a nontrivial automorphism of the complex field $\mathbb C$. In set theoretic terms, the question is whe...
Recently, an answer was posted and it is not accepted. (I do not know enough to be able to judge the correctness of the answer.)
« first day (1671 days earlier) ← previous day next day → last day (2254 days later) »