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SmokeDetector
SmokeDetector
3:51 AM
[ SmokeDetector ] All-caps title: A - (B Δ C) = (A - B) - C by parmvirchahal on math.stackexchange.com
 
 
8 hours later…
Martin Sleziak
Martin Sleziak
11:35 AM
I have added to the title domain and codomain, to stress the difference pointed out by @egreg. (And I have also retraced my close vote. I should have read the question more carefully.) — Martin Sleziak 59 secs ago
The question If $f:[0,\infty)\to [0,\infty)$ and $f(x+y)=f(x)+f(y)$ then prove that $f(x)=ax$ is different (although related) from the usual formulation of Cauchy functional equation. (Which is about functions $f\colon\mathbb R\to\mathbb R$.)
Is seems that several users (including me) missed this difference.
You can vote to leave open here. (Or to close as a duplicate, if you can find a question which indeed is a duplicate.)
 
 
1 hour later…
Martin Sleziak
Martin Sleziak
1:04 PM
Notice that the older question asks for integral domains. And also that it specifically asks for examples different from $k[x_1,x_2,\dots]$.
 
Martin Sleziak
Martin Sleziak
1:25 PM
BTW the older question already has two votes to close as off-topic. (I am not sure to which extent they are deserved.)
If it is closed, we might end with not very good situation that a question is closed as a duplicate of closed question. Which would be a pity - it seems that both questions have received some reasonable answers.
 
 
4 hours later…
Will Byrne
Will Byrne
5:24 PM
I think the request to close could have been prompted by what was a little bit of a heated discussion in the comments between me and @user26857. For the record, I do think these are distinct questions and are worthwhile keeping.
 
 
2 hours later…
SmokeDetector
SmokeDetector
7:46 PM
 

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