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Jan 25, 2014 at 17:35 vote accept Alexander Gruber
Jan 25, 2014 at 15:01 comment added Emil Jeřábek And in order not to dump all confusion on Archimedes, $\mathbb R$ has rank $1$ as an ordered abelian group, but rank $2^\omega$ as an abelian group.
Jan 25, 2014 at 14:24 comment added Emil Jeřábek Right. And conversely, any nonarchimedean ordered field of cardinality at most $2^\omega$ carries an archimedean absolute value (induced by a field embedding into $\mathbb C$).
Jan 25, 2014 at 14:14 comment added Torsten Schoeneberg Ah, of course, thanks. (In this setting the terminology confused me: So a DVR has a non-archimedean valuation with archimedean value group ...)
Jan 25, 2014 at 14:03 comment added Emil Jeřábek @TorstenSchoeneberg: A totally ordered group $G$ is archimedean if for every positive $a,b\in G$, there exists an integer $n$ such that $a\le nb$. This is equivalent to having rank $1$.
Jan 25, 2014 at 13:42 comment added Torsten Schoeneberg @EmilJeřábek: Is "discretely ordered but nonarchimedean value group" what you really want to say? I would have expected "value group that is discrete but not of rank 1". -- Btw, your answer is amazingly elegant.
Jan 25, 2014 at 12:09 comment added Jesse Elliott Also related: mathoverflow.net/questions/36611/…
Jan 25, 2014 at 0:09 comment added Torsten Schoeneberg Related: mathoverflow.net/questions/30715 , mathoverflow.net/questions/39866
Jan 24, 2014 at 22:36 answer added Emil Jeřábek timeline score: 10
Jan 24, 2014 at 21:09 history edited Alexander Gruber CC BY-SA 3.0
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Jan 24, 2014 at 20:21 answer added Fred Rohrer timeline score: 4
Jan 24, 2014 at 19:58 comment added Emil Jeřábek Any valuation ring with a discretely ordered but nonarchimedean value group is a counterexample to the statement you claim to be true in 1. And for any field $K$, $K[x]/(x^2)$ is an example for the second part of 1.
Jan 24, 2014 at 19:46 history asked Alexander Gruber CC BY-SA 3.0