« first day (585 days earlier)      last day (4730 days later) » 

20:01
@tb Yes : ) I'll try to get this Additive Combinatorics thing done.
Hah! I am not getting to sleep at all. :/
Have you been doing thinking before you went to bed? : )
Holy monkeys rattling on your chamber door?
For some weird reasons, it is the third time, I am logging into SE in an hour.
20:04
Weird. I just stay logged on all the time. : )
Several attempts to forcibly close my eyes have ended in vain. So, I aam going to wait for it to happen naturally.
But it's only 1:30 am there, so not that late.
@leo got it?
@MattN True. : )
@KannappanSampath We could talk about numerical mathematics that should do the job.
20:07
@MattN Sure. I am in.
@MattN given that commutative algebra doesn't do the job, I'm somewhat skeptical...
@tb I think you like CA, secretly, you're just too shy to admit it : )
Commutative algebra is only when I am alive. (any form of algebra is only when I am alive!)
@KannappanSampath Ok. For example: there is this very exciting method, called trapezoidal rule, to approximate the integral of a function.
20:10
Say you want to integrate $f(x)$ between $0$ and $1$.
@MattN well, you can prove Stirling's formula with it :)
Then, consider the trapezium enclosed by $x=0$, $x=1$, $y=0$ and the line joining $(0,f(0))$ and $(1,f(1))$-Is that the next step?
Yes : )
Well, wait: what's that $y=0$?
You have $4$ points already.
And then wooow, we have an approximate value of the integral of the function. Are you still awake?
It's clearly terrifically booooooring. : )
@tb Of course, I did not know that : ) Thanks for pointing it out.
@KannappanSampath Well as you're still awake let's do some more.
20:16
@MattN BTW, I wanted to ask you if you're reading Additive Combinatorics by Tao?
@KannappanSampath Yes, I am.
Oh, I see.
How is the book written?
(Too elaborate like his Analysis texts?)
It uses a lot of notation I don't like. And I think its target audience are advanced students. Or clever ones. I'm not sure which.
I am neither at all. : )
@KannappanSampath No. I'm not sure how to describe it but I don't think I like it. OTOH, I don't want to decide just yet because I haven't read very much (because progress is slow because it's no fun so far)
20:20
@MattN See here
@tb Apparently I can only look at the preview using webvpn.
@tb I'm confused.
"Department of Psychology, University of Hawaii"? : )
Oh I see, the article starts at the bottom.
That's the author of the previous note, the one previous to what tb points out. :-)
Yes, I just noticed. : )
@MattN strange. Might be JSTOR's abysmal cookie system, try to clear them while you're still using webvpn. Anyway, here's a freely available text doing something very similar.
20:37
Thanks : ) Ok, so it's not as boring as it seems.
Why are people so insistent about writing the curl of a vector field as $\nabla \times X$?
Well, apparently because "The notation ∇×F has its origins in the similarities to the 3 dimensional cross product, and it is useful as a mnemonic in Cartesian coordinates if we take ∇ as a vector differential operator del. "
(But I'm quite sure you knew that already : ) )
Thanks :) I'm just curious because people are very eager to suggest edits doing that (well, I'm exaggerating, but it happens from time to time). I never liked the notation people use in vector analysis, I always found it more confusing than helpful, but apparently, I'm part of a minority...
Would you write $\operatorname{curl}{F}$?
Kannappan, are you still awake?
Yes, but more active than before, : )
20:49
@MattN I don't know what I would write. But I would not suggest an edit to replace $\operatorname{rot}{F}$ or $\operatorname{curl}{F}$ by $\nabla \times F$.
@tb I guess you can always start a meta thread on this...
@MattN Oh, do you think I should? :)
Just edited it!
20:52
The cat just forced herself between me and the laptop : )
@MattN actually, I'm glad we had this meta discussion. It clarified a lot and we now know exactly how to react.
@MattN Does she want you to watch Dr. House without distraction by the chat?
@tb No : ) She's more into watching mouse pointers...
@tb I definitely do: don't edit wrong English. : )
@tb Do you watch House?
@MattN No, I've never seen it. I don't have a TV and the web thingies only broadcast the synchronized versions and that spoils the fun for me...
@tb But the web thingies broadcast in English : ) But never mind.
Also, doesn't iTunes sell it?
(It's not that great, you don't miss much)
21:10
@MattN I haven't tried very hard and I'm pretty sure iTunes sells it. Let me put it this way: I already have enough methods to waste my time effectively so I don't pursue other approaches actively...
@tb I can see that. : )
For example this chat.
For example...
That came out a bit wrong.
@KannappanSampath There are more methods to approximate integrals...
There is for example Simpson's rule.
That's almost as exciting as the trapezoidal rule.
I think he fell asleep. No surprise. : )
Numerical methods work like a charm.
How can a question have a close and an up vote at the same time?
Although "effective approach to compute the homology" of an empty thing doesn't seem to make sense.
21:27
I feel smart because of my answer to that definability question.
The saviour. Interrupting my monologue. Thank you.
Hello there. Could you solve your integral?
How did you do it?
21:31
By symmetry the xy part vanishes
Then you are only left with 3 times the area of a halfsphere with radii 2
Is there any questions on the site proving that eventually (when $x>n$ ) $n^x > n^x$ for all $n>1$ ?
There's something wrong in your formula... Anyway: I suggest that you take logarithms.
Oh sorry, I was only messing around in geogebra =)
It seems that n^x when n>1, eventually increases faster than every finite polynomial.
That's true. This basically reduces to the series representation of $e^x$, as follows:
For $x \geq 0$ you have $e^x = \sum_{n = 0}^\infty \frac{x^n}{n!} \geq \frac{x^{n+1}}{(n+1)!}$.
Now a polynomial of degree $n$ grows at most as $C x^n$ for $C$ large enough, that is $C x^n \geq p(x)$. Thus for $x \gt C (n+1)!$ you have $e^x \geq x \cdot \frac{x^{n}}{(n+1)!} \gt C x^n \geq p(x)$.
Now for $y \gt e$ you have $y^x \geq e^x$... Piece those things together and done.
21:47
Does this only for for polynomials of degree at most n ?
Your argument is logical, I am just asking =)
Well, I've shown that for every polynomial $p$ you eventually have $e^x \geq p(x)$. Indeed, it shouldn't be hard to modify this argument to show that $\frac{p(x)}{e^x} \,\xrightarrow{x \to \infty}\,0$. Does this answer your question?
@MattN by having two different people voting at the same time? Anyway, the paradox seems to be resolved now...
@tb Yes. And yes.
@MattN Oh, I just didn't want to interrupt your lullaby for Kannappan :)
I upvoted that question just now to compensate for another unnecessary down vote. I've been doing this a lot lately.
@MattN I didn't vote on that question but it strikes me as a horrific one. Just plug in the definitions, for crying out loud.
leo
leo
22:00
@tb, got it :)
@leo Great! I gathered that from the vote I got :)
@MattN You may also want to look at this meta thread.
@tb That's the person about whose opinion I care least.
@MattN I am not usually in agreement with Qiaochu's approach, but I completely agree with that point on pity voting.
When something is downvoted to begin with it's sort of a signal to the rest of the community that this post should be carefully looked into.
Yes, I think we disagree on this : )
On the other hand, when I see a post by someone whom I trust to write a good post, I am willing to vote blindly.
22:10
I don't see any benefit to down voting, even if it makes you "feel all powerful" and whatnot.
Now that is a plain try to get the Enlightened badge, and whatnot.
Makes me want to downvote that out of spite.
@AsafKaragila looks more like an accident to me...
No, actually it doesn't.
@tb Yes, it is obviously an accident with [to be continued...]?
I think not.
What Asaf said.
I don't like him anyway.
22:13
Why did you remove your angry comment?
It's not my job to be this site's parent.
Agreed.
If anything, flagging it and pointing out he is gaming the system...
leo
leo
about Vitali sets and other devils...
@leo Who said the axiom of choice?
22:15
Oh noes I have to go to bed soon. (apparently)
So much for the last, non-teddy-reduced evening.
@leo what are you talking about?
leo
leo
@tb nothing. Just type it
Can someone tell if there is a count of the number of topologies on a finite set?
@KannappanSampath the exact number isn't known but there are good estimates for the asymptotic growth. But gee, you should be sleeping now!
leo
leo
@tb I mean: of Vitali Sets and Other Demons
22:20
Almost 4 am : O Numerical maths didn't work at all : /
I am just not able to sleep. So, trying to read up Munkres.
Me probably neither but I don't have much choice. Good night folks.
Don't stay up all night.
leo
leo
@MattN Sleep well
Good night, Matt
Good night, Matt.
22:24
Gute Nacht, Matt!
@KannappanSampath This is one of the standard references for this problem.
@tb Thank you for the reference, I thought a closed formula should be feasible. No?
This is about as close as it gets to a closed formula.
Oh, Thank you. I should have asked wiki first. Sorry for troubling you.
@AsafKaragila The answer's gone now (now that he thinks he's got it where he wants it...)
22:36
Yeah, I saw.
Hey Kannappan
For some reason I'm reading an article on Asperger's now.
@KannappanSampath. Hi kannappan!Long time!
Hi all!
@FortuonPaendrag How have you been?
Finally got some values from my symmetric group problem
22:39
I am going to sleep now.
@JohnSmith Oh, I see. Did you read up on the groups?
@JohnSmith Was my answer useful at all?
@KannappanSampath: Quite Decent, thank you. I should be asleep, since I have an exam tomorrow, but I am restless.. How about you?
Good night, Asaf
@AsafKaragila See you tomm. Asaf. : )
Yes I understand a bit more about it now
Still not getting the right answer but at least I know what's going on
Thinking it's now a precision issue
22:41
I need to stay up for a short while, I'm all restless and whatnot.
@AsafKaragila Gute Nacht!
@FortuonPaendrag I should be asleep now too. I would like to tell you, catch some sleep, it helps think better.
@MattN what's up?
Bitte.
@KannappanSampath Haha. I have a question that I fear might be too trivial to post as a full question, so can I ask you?
22:43
@FortuonPaendrag Sure, if I know it I will definitely help you. Anyway, the whole room will help you too given you have exams tomm. : )
In a normed space, if two vectors are linearly independant, is the sum of their norms equal to the norm of their sums?
@tb Not sure. Thanks for asking. I think I just had a bad day.
leo
leo
@FortuonPaendrag no
I'm thinking about reducing my time on chat. I feel like it's out of control. I don't like it when things are out of my control.
I am not familiar with these objects. I'll leave it to the room.
22:45
Ah, euclidean space of course. @leo
@FortuonPaendrag no. of course not. Try $\mathbb{R}^2$.
@KannappanSampath, you were right. I should sleep.
leo
leo
@FortuonPaendrag Take (1,0) and (0,1) in $\mathbb{R^2}$
with the euclidean norm
Hah, I could have thought too. Right @leo.
Thanks guys. facepalm
leo
leo
22:47
@FortuonPaendrag Why you need that? what are you trying to prove?
@MattN I can totally relate to that feeling...
(both chat-related and the other one)
If a sequence in a finite subspace of a normed space is cauchy, then its coordinates wrt a fixed basis of the subspace must be cauchy too. @leo
@tb : )
leo
leo
@FortuonPaendrag by finite you mean finite dimensional, right?
Btw, what I wrote about punching in the face: that was a joke and I should've put a ": )" there. I'd not punch you in the face.
22:51
yes, it is spanned by a finite basis set. @leo
@MattN Oh, you meant me there? I hadn't interpreted it that way. I was just pointing out that some people don't like pity upvoting. And I haven't voted on that question, btw.
@MattN Why would you want to do that? I am sure you're joking. : )
22:55
@KannappanSampath I don't mean literally. But yes, non-literally I'm dead serious. : D
does anyone know of good linear equation solvers?
I have a 55-variable deep system with some large decimal figures and I worry about precision issues
Sounds like a job for matlab/octave
@tb So you don't like feelings in general? Iirc you said that feelings aren't simple to control...
Oh dear. Maybe I should solve some integrals numerically...
Are all our systems failing to see the need to sleep?
Yes.
23:00
You bet :P
leo
leo
@FortuonPaendrag, maybe by induction on the dimension of the subspace
@FortuonPaendrag prove that the projection on one coordinate is a continuous map (you can do that by induction on the dimension, as leo suggests).
Ah, I had not considered induction. I will try.
@MattN It feels like it is impossible to react to that in a sensible way. I wouldn't put it in those general terms... But I do have the feeling that oftentimes feelings aren't actually helpful. :)
Thank you! @leo @tb
and the room in general!
leo
leo
23:04
@tb I am tempted to say that such a space is isomorphic to some $\mathbb{R}^n$ and then the result holds
@tb : ) It was more of a silly question. It's quite late and the later it gets the sillier I get...
leo
leo
since it is true in all the $\mathbb{R}^n$
But of course, a serious answer is also appreciated!
@KannappanSampath You should really go to sleep.
2
@leo Sure, but in order to prove that you actually prove much more...
@MattN Sure. I am going to sleep now. : )
23:06
Good night! : )
Goodnight! :)
@KannappanSampath good night, and never mind the monkeys!
leo
leo
@KannappanSampath good night!
Bye all. (And sure @tb)
Holy monkeys.
leo
leo
23:08
buenas tardes @MarianoSuárezAlvarez!
Hi, Mariano
leo
leo
:-)
Hi Mariano.
(problem solved)
I assumed he was on the American continent. But actually, I have no idea where he is. : )
leo
leo
I dont't know in Argentina, but here is afternoon
I'm to the north of Mariano
Oh! Yes. It's quite late here.
23:13
And back he is: go to bed, now, Kannappan!
I'm too bored and too restless to sleep.
@tb I think that was just an accident : )
@tb You're the one to talk anyway.
@t.b. Haha, for a second, I could hear my dear mother :D
She can be quite terrifying.
@MattN But it most likely means he isn't asleep, doesn't it?
23:15
@tb Well he might've brushed his teeth and then decided to check his emails for a second before going to sleep...
@FortuonPaendrag : D
@MattN It is one of my strengths to give advice I myself don't follow :/
@tb Is that a strength? Is that what you say in a hiring interview when they ask you "What are your strengths and your weak points"? : D
@tb I should get rid of this teddy bear mental image I have of you. It makes me want to pick you up from the floor and take you to bed with me. : D
7
@MattN exactly. Right after I mentioned that I'm terribly disorganized and lousy at staying focused, especially on things I'm not particularly interested in...
I can relate to that last part : D
@tb Its not just you I am there to give you company in being terribly disorganized and lousy at staying focused, especially on things I'm not particularly interested
:)
23:22
Sivaram, have you started working through Atiyah?
In the first chapter, moving at a snails pace
how about you?
@MattN, do you mean his commutative algebra?
Not yet. I need to finish a presentation first. I'll start next week.
@FortuonPaendrag Yes.
@SivaramAmbikasaran Hi, Sivaram! Nice to meet you here :)
Im working through Reid's right now.
23:24
How is it?
I really like it!
Of course, Im not flying through the pages
but that was to be expected
@MattN My progress will be slow for sure given the $\infty + 1$ research deadlines coming up.
Well good, then you might just about match my pace, I'm slow.
Hope to work more during the spring break which comes after three weeks
@FortuonPaendrag Thanks for mentioning that, I think I'll have a look at that too. I hear Atiyah is no fun to work with.
I think I'll force myself to log out of this chat and go to bed.
23:27
@MattN You are welcome!
@MattN I heard it's very good. I read his Undergraduate Algebraic Geometry a long time ago and it was excellent, so I guess his commutative algebra will be of similar quality.
Good to know.
@MattN Sleep well! And hopefully feel better tomorrow! :)
Good night, Matt!
Thanks : )
@Teddy: It's your bedtime too. So don't stay up all night.
23:29
@tb What about Atiyah and Macdonald?
Hi, Ben!
hey you guys discussing about AM?
I have just started reading the first chapter, am I am a very slow learner.
The first couple of chapters seems readable but the problem with me I lose the bigger picture and get stuck too much on details
@tb If $m$is the maximal ideal contained in a local ring, $N,M$ submodules of an A-module M and $N + mM = M$, then why is $m(N+ mM/N) = M/N$?
@SivaramAmbikasaran Do you know some general topology?
I have read the first four chapter from Munkres and first three chapters from Topology without tears
23:32
Ok then no problem for you then :D
@BenjaminLim No not exactly, the problem as I said before is I lose the bigger picture and get stuck too much on details
Well you should try the last two problems of chapter 1
Very good
I do not seem to understand the motivation for certain things especially in algebra
And I have asked on how to do some of the problems on AM on the main site, you can check them out if you want :D
Oh sure that will be of help
@SivaramAmbikasaran I'm in no position to judge. I heard all kinds of opinions on it. It seems quite terse and lots of important information seems to be in the exercises. I guess that means it's not for the faint-hearted. I tried to read it a long time ago but I wasn't terribly excited, but commutative algebra is not really my cup of tea anyway.
@BenjaminLim You should be aware of the fact that you already know more algebra than I do...
@tb Vous êtes fou?
No, I'm pretty serious :)
Why would you say that?
Because you keep asking me questions on algebra with the expectation that I can answer them... Well, maybe I could, but I never learned algebra properly.
23:39
@tb What about me? I am just self taught mainly and have almost zero peer support here.
Yes, but you're learning it right now, so you're much more into it than I. You apparently haven't made the experience of how much you can forget in a few years of not using something at all.
@tb I get what you mean :D
@BenjaminLim , if it makes a difference, Im teaching myself Comm Alg out of Reid right now too :)
@FortuonPaendrag What chapter are you looking at now? Are you looking at modules?
Yes, I've just set foot in that chapter today.
23:44
Ok excellent when you reach Nakayama's Lemma ping me :D
Will do! :)
What is the approach to determining accumulation points? I can not find any examples of this being done. Does anyone have any pointers?
@FortuonPaendrag Where are you now in the world?
In Budapest.
And yourself? @BenjaminLim
canberra, australia
23:47
@arete what setting are you working in? Subsets of $\mathbb{R}^n$?
i'll go now and continue on modules
Goodluck!
I should go to bed too.
@arete maybe the examples here are of some help?
@FortuonPaendrag yes, do that, and good luck with your exam tomorrow!
@tb Here is the problem I am working on mathbin.net/90455. I will look through the chapter you gave me now.
@arete I see. So you're supposed to determine the limit points of $S$?
23:59
@tb. Yes. I have a good understanding of what a accumulation point is. I am at a loss though of how to go about determining them. Especially proving that those are the only ones.
By the way, if you head over here you can find a link to a bookmarklet that allows you to see the latex rendered here.

« first day (585 days earlier)      last day (4730 days later) »