https://math.stackexchange.com/questions/451846/why-r-fracfn

https://math.stackexchange.com/questions/450899/left-a-n-a-1-a-n-a-2-text-a-n-a-m-text-right-varepsilon

$\xi$ is the least upper bound of $M$.

https://math.stackexchange.com/questions/450937/dedekinds-theorem-are-they-the-same

Why so many downvotes? my questions is too dummy? me dummy sorry.

How to avoid downvotes? I'm new here.

• Some of those downvotes might have been consequence of serial voting, in which case they will be reversed. Jul 25 '13 at 13:23
• @MartinSleziak: I got -4k some days ago. Some of my students gave me more + without regarding the site policy. I am a loser. :( Jul 26 '13 at 18:18
• @BabakS. Oh my. Did you get +4339 for all the votes? With a max of 200 a day, that would take weeks. So, why would you lose them all at once? Just to be clear, I'm asking, if you got 1000 upvotes by a few people in one day, you'd only get +200 rep. Would you get -5000 when they were reversed? Jul 27 '13 at 2:18
• @Graphth: Dear friend, I have not found out what exactly happened in days ago for me yet. The only thing I could get was that some of my students who were suggested to be here as users, made me + more than the legal level. This story was passed and I am OK with it. ;-) Jul 27 '13 at 16:02