Timeline for The sum of two well-ordered subsets is well-ordered
Current License: CC BY-SA 4.0
8 events
| when toggle format | what | by | license | comment | |
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| Jan 18, 2021 at 16:22 | comment | added | Elliot Glazer | It's also worth mentioning that, while some amount of choice is needed to prove that every ill-founded ordering has a descending sequence, this argument requires no choice since $A + B$ has an induced well-ordering from $A$ and $B,$ so this descending sequence can be canonically constructed. | |
| Jan 18, 2021 at 14:57 | comment | added | Alessandro Codenotti | Those kind of unexpected applications of Ramsey's theorem are really beautiful! | |
| Jan 18, 2021 at 14:10 | comment | added | Nik Weaver | You are welcome! This version of Ramsey's theorem is worth remembering, it comes in handy every now and then. | |
| Jan 18, 2021 at 13:58 | comment | added | abx | Great, thanks! Glad to see that it is not completely trivial — at least for a non-expert... | |
| Jan 18, 2021 at 13:57 | vote | accept | abx | ||
| Jan 18, 2021 at 13:43 | comment | added | Nik Weaver | Trust me, you've beaten me by more than 10 seconds many times ... | |
| Jan 18, 2021 at 13:36 | comment | added | Wojowu | Beaten by 10 seconds! | |
| Jan 18, 2021 at 13:36 | history | answered | Nik Weaver | CC BY-SA 4.0 |