Timeline for Number of countable torsion-free groups
Current License: CC BY-SA 3.0
6 events
| when toggle format | what | by | license | comment | |
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| Nov 12, 2017 at 17:38 | vote | accept | Dominic van der Zypen | ||
| Nov 12, 2017 at 16:14 | comment | added | YCor | This can also be stated as: the ring $\mathbf{Q}$ possesses $2^{\aleph_0}$ subrings (these are precisely the $\mathbf{Z}[S^{-1}]$ when $S$ ranges over subset of the set of primes) and these are pairwise non-isomorphic as additive groups (because for every prime $p$, we have $p\in S$ iff multiplication by $p$ is surjective in $\mathbf{Z}[S^{-1}]$). | |
| Nov 12, 2017 at 15:59 | history | edited | YCor | CC BY-SA 3.0 |
started with the main statement
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| Nov 12, 2017 at 15:17 | history | edited | Jason Starr | CC BY-SA 3.0 |
deleted 15 characters in body
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| S Nov 12, 2017 at 14:27 | history | answered | Jason Starr | CC BY-SA 3.0 | |
| S Nov 12, 2017 at 14:27 | history | made wiki | Post Made Community Wiki by Jason Starr |