Timeline for Quotients of posets
Current License: CC BY-SA 3.0
12 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Nov 11, 2020 at 17:15 | comment | added | Todd Trimble | @creillyucla That's right. | |
| Nov 11, 2020 at 15:46 | comment | added | creillyucla | Just to clarify, in the statement "...the quotient R where x,y∈Q are identified if x≤y and y≤x in Q.", does ≤ refer to the afore-mentioned preorder (not necessarily antisymmetric) on Q? | |
| Oct 13, 2015 at 19:33 | comment | added | Todd Trimble | @GejzaJenča That makes sense, as internal equivalence relations in a category are also called congruences. | |
| Oct 13, 2015 at 19:19 | comment | added | Gejza Jenča | Four years ago, I spent some time trying to google-guess how are these things called by people working in poset theory. The answer is "order congruences". | |
| Oct 1, 2015 at 19:30 | vote | accept | Dominic van der Zypen | ||
| Oct 1, 2015 at 19:04 | comment | added | Todd Trimble | @BorisBukh I would likely not have answered if there were already votes to close at the time of writing. In this case, the "amount of effort" can only be a guess. Maybe you're "right" in your judgment call; I don't know. But I respect the decision you made. If you want to continue the discussion, I suggest meta or chat, or you can mail me or the moderators if you like. | |
| Oct 1, 2015 at 18:51 | comment | added | Boris Bukh | The "research-level" is a relative term indeed --- in a normal course of research one faces questions of varying difficulty, from trivial to insurmountable. One might have a mental block on otherwise-easy problem, too. However, one must always make an effort. If a problem is genuinely easy, giving a hint or referring to MSE is the right thing to do. In a case like this, where seemingly very little effort went into the question before it was asked, even that is too charitable. Such a question must simply be closed. | |
| Oct 1, 2015 at 18:38 | comment | added | Todd Trimble | @BorisBukh I wasn't implying that that would make it "research level" (whatever that means exactly: it's such a relative term, cf. the fact that many logic questions get asked that a logician would consider elementary). The appropriateness for MO I leave for others to judge for themselves; I think it's plausible that this is something that a graduate student or non-expert mathematician might ask of another, in keeping with the original vision for MO. Also, while you might be right that not much effort went into the question, I did foresee that something interesting could be said. | |
| Oct 1, 2015 at 17:58 | comment | added | Boris Bukh | I do not understand how "there are several ways of looking at it" makes the problem research-level, or demonstrates that OP put effort into the question before asking it. I am downvoting this answer as it encourages more non-research-level questions on MathOverflow. | |
| Oct 1, 2015 at 16:26 | history | edited | Todd Trimble | CC BY-SA 3.0 |
fixed some typos
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| Oct 1, 2015 at 14:03 | comment | added | Todd Trimble | The need to go an extra step by taking a posetal reflection can be seen in simple examples. For example, if $Y$ is the poset which looks like $(a \to b\;\;\; c \to d)$ and $X$ is the discrete poset $(p \;\;\; q)$, and if we define $f$ by $f(p) = a, f(q) = b$ and $g$ by $g(p) = d, g(q) = c$, then the preorder quotient looks like a loop on two points, hence not a poset. The posetal reflection of that collapses to a point. | |
| Oct 1, 2015 at 13:34 | history | answered | Todd Trimble | CC BY-SA 3.0 |