Conversation started Mar 31, 2013 at 0:51.
Mar 31, 2013 00:51
@anon any help with this :
what is the set of positive interger n for which $(2n+1, 5)=1$
step 1: what is the set of positive integers m for which (m,5)=1? step 2: restrict to odd m.
@pourjour excellent!
@PeterTamaroff I am now.
@anon m are those that cannot be divised by 5 am I right?
alternatively, (2n+1,5)=(2n-4,5)=(n-2,5), so whenever n is 2 more than a number coprime to 5
Mar 31, 2013 00:54
@BrianM.Scott OK. We assume $B(x,\epsilon)\cap G$ is empty. This means that there are no numbers inside $(g,h)$ for $g=\sup\{g':g'<x-\epsilon\}$ and $h=\inf\{g:g>x+\epsilon\}$.
But before, I said that there were some $g,h\in G$ that worked.
I think it needs to be justified.
@anon can't understand this "so whenever n is 2 more than a number coprime to 5"
@PeterTamaroff All that has to be justified is that $G\cap(\leftarrow,x)\ne\varnothing\ne G\cap(x,\to)$.
@BrianM.Scott OK, but we said that such $g,h$ were such that no $\ell \in G$ satisfied $g<\ell <h$; or did I say it and wasn't corrected?
@PeterTamaroff See my first comment in the one where I described a sentence as awful.
@BrianM.Scott =)
Mar 31, 2013 00:59
So markov processes are defined on continuous spaces. Markov chains are the discrete counterpart. Markov chains have a continuous time version. But I can't find anything about continuous time Markov processes.
Is there any reason why Markov processes can't be time-continuous?
@BrianM.Scott What I'm wondering then is: how do we prove $G\cap (h,g)=\varnothing$?
@PeterTamaroff What is there to prove? Every element of $G$ is either $\le h$ or $\ge g$ by the definition of $h$ and $g$.
@BrianM.Scott Sorry, how did we define $g,h$?
@anon I think the set of n is $S=\{ n : n=5p+k : p\in \mathbb{N}$ and$ k\in\{0,1,3,4\}\}$
that's correct
Mar 31, 2013 01:06
@PeterTamaroff You did it about half a dozen comments back.
@BrianM.Scott the infs and sups?
@anon does p must be a prime?
@PeterTamaroff Yes.
@pourjour $p\in\Bbb N$ is what you wrote, and what you wrote is correct
@BrianM.Scott Oh, sorry. I thought that didn't work. I think I lost confidence.
Mar 31, 2013 01:07
@anon and k=0 or 1 or3 or 4
??
yes
@PeterTamaroff Oops! My fault: no, those don’t have to belong to $G$, so a little more work is needed.
@BrianM.Scott That's why.
@anon thanks
@anon is there any other way without noticing this $(n-2,5)=1$
?
 
Conversation ended Mar 31, 2013 at 1:09.