« first day (451 days earlier)      last day (4865 days later) » 

16:00
@Sri : i am doing PhD at iiit hyderabad...guess you have heard about it
Yes, I have.
@Srivatsan: Wasn't that strange that the guy used \align without actually using the multiline properties?
Oh yes. Is it the case that he is self-learning TeX from examples? Surely someone must told him about single line equations...
@Asaf @Sri : i need to seek a clarification and looking at this answer would give a quick idea......
2
A: Does a function and its Hilbert transform have the same behaviour?

robjohnSince the Hilbert Transform is defined as $$ f_h(t)=P.V.\frac{1}{\pi}\int_{-\infty}^\infty\frac{f(t-x)}{x}\;\mathrm{d}x\tag{1} $$ at any jump discontinuity, $d$, of $f$, $f_h$ blows up like $\frac{D}{\pi}\log|t-d|$, where $D$ is the size of the jump discontinuity at $d$. Furthermore, $(f^{(n)}...

I don't even know what the Hilbert transform is...
16:07
Can't speak for Asaf, but I am perhaps a wrong person to ask.
@SrivatsanNarayanan If you're perhaps then I'm surely :-)
ok.....i still think you may.....as it is not any expert level doubt...just that i am not able to get my mind to think in a mathematical way but still need an answer for a doubt
Um, if you say so :). So, what's your analysis background?
Reading the post, Rajesh.
Morning
ok... does 1/|x| belong to L^p
?
16:10
Good afternoon, Matt.
GM Matt
actually its night here
I am trying to understand a simplication Wolframalpha made, anyone care to take a look?
Sure, post it. I have a feeling @Asaf is ready to pounce on it when he gets a chance. ;)
haha
Let me know if that link works
Yes, it does. What's the simplification btw?
(@Rajesh 1/|x| belongs to L^{p >1} but it's not in L^1.)
16:14
-4sin(^2)t - 9cos(^2)t --> 5sin(^2)t-9
If you goto show steps where it shows what t = , you'll see that simplification, its the 2nd step
ok....got it.thanks @Sri...that was basically about it
To go from right to left, write 9 as 9 c^2 + 9 s^2 and simplify. To go from left to right, write c^2 = 1-s^2 and simplify.
@SrivatsanNarayanan Wha?
Ah, ok a trig sub, eh?
Of course, I adopted the universal convention that c=cos t and s=sin t. :-)
16:17
@SrivatsanNarayanan So your field of expertise is Cos(Sin t)? ;-)
Thanks
Sorry, @Asaf. One of these days I am going to be charged for attempted humor.
Well, CS :-)
Hmm
That would be cos t \cdot sin t, but ok :)
16:20
I have a problem asking Determine ∫(vXa)dt
Where v and a are vectors
Yay, who prefers cdots in chats?
X is cross product
Is this question too vague to solve?
Or should I just assume 3d
and let v= <a,b,c> and a=<x,y,z>
Are "v" and "a" functions of t? Do they secretly go by "Velocity" and "Acceleration"? :)
No, "vector" and "arbitrary vector" :-P
ah yea, they may
Because this is a multi-part proble,
and I am initially given a vector r(t)
So I can derive a(t) and v(t)
Good thinking
16:24
I am glad Matt appreciates his own thinking. :-)
I wish they had allowed for Latex equations in chat ....is it already there !
What the... I edited some TeX replacing >= with \ge and someone undid it claiming it was "mathjax misuse"
lol
Well, Rajesh, we do secretly like to speak LaTeX code, don't we?
@Asaf That is an edits abuse. :) Doesn't he know that even rolling back incurs an extra edit? (Also we should warn them that $\ge 10$ edits will make the post CW.)
16:31
a and v are both only 2 dimensional though
i've only ever done the cross product in 3d
What ever shall I do?!
Wait, I'll try to summarize what I understood.
@Asaf Do you know why some (many?) people use \Leftrightarrow for iff, \Rightarrow for \implies and \Leftarrow for \impliedby? It always bugs me when someone doesn't use the beautiful implies sign.
Should I just assume the j component is 0?
Probably the question intends the vectors to be in R^2, @Matt. If v = v1 e1 + v2 e2 and a= a1 e1 + a2 e2, then v cross a = (v1 a2 - v2 a1) e3.
Why is the **j** component zero?
what is e?
(besides 2.718)
(^ bad math joke!)
its (1+1/n)^n as n -> 0...i guess
@Matt : was that a question ?
16:43
yea
He has e1, e2, e3
Oh sorry, @Matt. It is not the Euler's constant. e1, e2, e3 are the unit vectors along the x, y, z directions
not sure what they are
euclidean basis i guess
ok
standard basis
16:44
Thanks
I gotta hit the road, see you all around
See you around!
@Sri how can i post a picture in chat ?
There's an upload button (please do use this option only if the picture is not large)
You can also upload it into imgur and post a link here. This works nicely for large pictures.
16:51
is there any alternative if the pic is not small
ok
you may want to have a say on this i.imgur.com/U2l59.jpg
A number of excellent answers are already posted. I don't have any more to add.
Is there a rep lower bound for posting answers to your own question? The OP says something to that effect here: math.stackexchange.com/questions/76935/….
no idea
but how he managed to post comment ?
strange
ok he can comment only on his posts...need 50 rep to comment everywhere
but for answering it is not mentioned to have any min rep
@Sri : what do you mean by brutus ?
17:11
@Rajesh: Those are Cesar's purported last words: Et tu, brute
(this question was asked at least four times here, recently)
So, it just means: another one who asks this question?
Sorry about not giving the full context, @Rajesh.
no wonder.......i had got it from FB.....hi t.b.
no problem atleast i learned a new word from it
Hi, Rajesh
@t.b. : i have a small question for you
Shoot!
17:15
why is it that you use small letters t.b. instead of say T.B. or simply TB ?
@tb I should've tried your style: You too, Brutus? =)
The comma is a separate link, by the way.
TB reminds me too much of tuberculosis and T.B. would have been okay, but somehow t.b. looks nicer to my eyes. I also wanted to avoid copying J.M.'s style.
2
So, no reason, really...
@Srivatsan: Speaking of copycats :)
okay
I attributed it to you. And ever heard of this: quotationspage.com/quote/27484.html? :-)
I hope you are flattered. =)
I am :)
Nice initials: c.c.c. :D
It's one of the worse misnomers in mathematics...
Oh, that's what they always say. I am surprised each time. =)
:)
(In the sense, something more inappropriately named always comes up.)
tb: So, can you say, in general terms, what's your plan for the next few hours? I haven't forgotten.
I'm gonna meet a friend for dinner soon, and the way these excursions usually end, I think I'm gonna hit the straw pretty soon afterwards. I tend to wake up with a headache usually on this particular day, so I'd prefer to know why...
17:29
hitting the straw.......something new for me to learn
But I'll drop by for a few minutes, and tomorrow, too.
Nothing in particular. I was wondering if you will be around at around* 12. (*speak of poor language)
Probably quite a bit later, unless you speak of 12 UTC, but I can't tell for sure, now.
But it's nice of you to remember it :)
Your time 12. :)
Let's see if I remember next year. I got clued in only a few days back.
It really depends on my and my friend's moods, but usually it easily gets 2-3 before we leave that place.
A nice Greek restaurant, just around the corners, and they don't let us go without trying to get rid of a year's reserve of Ouzo.
17:34
It's the day to enjoy I guess.
@Rajesh: That's not quite what I meant :D
a simple google search gave me that
i will think it is unless you tell me about it
I meant: drop into my bed.
ok
i think its time i hit the straw now
17:36
Good night!
@tb idioms.thefreedictionary.com/straw. I have heard it as "hit the sack" here, and I subconsciously understood what you mean. The "hit the straw" idiom is not on the list.
(I don't know if people say that in English, in fact.)
Oh, Srivatsan's beaten me to it.
@tb But it is hilarious to picture you and your friends acting out that video. =)
Good night, @Rajesh
Well, maybe "hay", instead of "straw" then. Pretty much equivalent for an urban guy like me.
OAE features "hit the hay"
17:40
Yes, Urban dictionary does anyway, so no more questions asked. :)
Woohoo, 5th person to win the "copy editor" badge: math.stackexchange.com/badges/49/copy-editor?userid=13425.
And, it's gold to top it off!
Congratulations!
Willie will follow soon, I guess, and I'd be surprised if it would take Michael too long :) There are plenty of superfluous braces to remove...
A brace police badge will be nice. =)
@SrivatsanNarayanan Shiny! Congratulations...
Thanks J.M. and tb. Simple pleasures--like gold--are what keeps a man going.
J.M., could you take a look at this and give your opinion?
By estimate, I meant the error estimate of O(1/n).
@tb Not that many people understand Latin anymore. Probably the translation most understandable to people nowadays is "dude, WTF?!"
@JM In this case, it wasn't the Latin that was the issue. Rajesh did not understand the reference to Brutus. (In all honestly, that name sounds more like an abuse. :))
@Sri: Looks to me Mike already said what I wanted to say. If I wanted to bound the error of an integral approximated with sums, Euler-Maclaurin is always the usual candidate.
I see. Thanks for that.
I know, I was commenting on why most of the kids nowadays won't get "et tu". :)
Yes, kids these days... =)
(Wonder if I am actually younger than Rajesh.)
17:59
Anyway, getting back to that integral: it's already conveniently expressed as the sort of sums you'd get with the trapezoidal rule, so Euler-Maclaurin naturally presents itself (which is why one of the comments under Mike's answer mystifies me all the more).
Yes, I couldn't make sense of it either.
Thanks for the comment, J.M.
I'm kinda bummed with this. I was going for the didactic approach, since OP had already shown that he'd tried some stuff out, and then suddenly there is a nice full answer.
(I upvoted the answer, but I'm still bummed.)
:-/ That answer is kind of too detailed, it seems to me.
Hm. Happened to me many times already... I don't know why people are so eager to answer questions, no matter what.
He seemed to already know how to do contours, so I was hoping he'd try to figure out where I pulled those integrals I gave him.
18:09
$$$ =)
Okay, it's the purpose of this site to answer questions, but I think trying to get people to think and figure it out by themselves is much more valuable than having an answer.
My take is that there should be an answer, but sometimes they appear too soon. If only we could make more of the posters post the solution, that'll be nice.
It's gonna take a whole lot of nudging from us "more experienced" users. At the very least, I've seen Arturo, Didier, and Gerry take up the campaign to nudge questioners to post the solutions they have as answers.
If we look at it from the rep viewpoint, if you post a neat solution to your own problem, an upvote will net you ten rep, as opposed to the measly two rep you get from accepting an answer.
I guess I won't fall in the "more experienced" category, but I tell new users whenever possible. But it sure is easier for me to just post that answer than to convince the OP to post the answer.
Of course, the more valuable thing to take away from that is a better understanding.
18:15
But sometimes the question is just so lazy that it doesn't merit more than a comment.
(I honestly don't know where you can learn about C*-algebras without finding that argument)
It sounds quixotic, but I do like Jeff Atwood's philosophy of "improving the Internet along with ourselves" when he started this whole gig.
Sometimes, the OP is unsure (about the solution, whether it's ok to post it etc.) or just plain lazy. I myself overcame a significant disinclination* when I answered my own question here: math.stackexchange.com/questions/68031. (*can't think of any better word)
A good thing you got over your reluctance. :)
Really? But that's a nice and well-thought out answer, so I see no problem with it at all!
In fact, I finally told myself that I shouldn't be advising inexperienced OPs to post answers if I cannot bring myself to answer my own question.
18:20
Well, the more experienced you get, the more you answer your own questions...
It wasn't the answer that was the issue, t.b. It was more a question of "should I be answering my own question?". Now I close that thought as not a real question.
:)
@Srivatsan: I dislike the longer arrows of \implies and \iff
I dislike "iff"
@Asaf: so you don't like \Rightarrow too?
Um, ok. I should I am surprised. What about you, J.M.?
18:22
I prefer \Rightarrow, it's shorter.
Ah, well, no further questions, Your Grace. ;)
I think it's time for posting the Why do mathematicians absolutely hate the long "implies" sign? question. :-)
No, you should go for your ravioli question, I choked on that one.
That's a meta question. Oh, reminds about the time somebody was railing about \mathbb... :D
That was fun!
18:25
When was this? I don't recall such a discussion.
I rarely use any of those logic signs in my prose. There's rarely any need for them.
Haha. I'm looking for some questions about induction on real numbers, and I ran into some question that I have answered and PEV wrote a one liner with a link to Wikipedia :-)
@Srivatsan: this one
Hehe apparently Wikipedia is a site about transfinite induction :-)
@tb Me too; I use \lnot sparingly, and I'd only use \land and \lor when forced...
18:27
@Asaf: seen this? :D
Of course.
This is why I brought that up.
@JM: I didn't even know that those existed.
I switched from \neg\wedge\vee to \land\lnot\lor actually.
It's clearer when you read it later on, and consistent with each other.
Makes more sense.
That's why I don't understand why Michael likes to use \text{d}x.
\operatorname!!!!
18:30
Yes, I must make that switch.
@Sriv: Congrats on the Copy Editor.
(apart from the fact that I don't understand why people would want that d upright)
@t.b. Okay, since I'm one of those people: that admonishment by Knuth on making that differential upright is not quite forgettable for me...
Haven't read that, sorry. It looks terrible.
Thanks Asaf. With regard to the upright d, I oscillate between this side and that. It kinda looks ugly when I write a lot of these integrals strung together. But I like it when there's a lone integral somewhere. For example, I made the "d" upright in the riemann sum limit answer.
18:33
Well, I suppose we have to agree to disagree. :) I've gotten used to distinguishing "operator" d's from "variable" d's...
...in the same way I'll probably keep using \mathbb R instead of \mathbf R for the set of reals...
I dislike the \mathbf notations.
Ah, I was of that opinion one or two years back. Everything changed when I read one of Terry Tao's books. Man, they look very beautiful to me now.
In my case, I tend to reserve \mathbf for vectors/matrices... nothing too deep.
Well, I learned about typography before I learned math typography, so maybe, that's an old remnant. It cost me dearly to use \mathbf in an answer recently, but I couldn't think of a nicer way to do it.
(although I'm all for abuse of notation in such cases)
"cost you dearly" - How so? And which answer? (I hope I am not too intrusive)
18:37
\cos(t)?
this one. It looks terrible.
Also, after reading math books of various typographical quality, I think I've settled a bit on my "mathematical aesthetics", or whatever the term for that is...
I was accused of "pulling a Dubuque" hint hint
"accused"? :)
18:39
whistles innocently
suppresses a giggle
shakes his head
feels sorry to have brought it up
Am I alone in thinking that \TeX and \LaTeX look ugly?
I am sure J.M. is thinking "Kids nowadays..." =)
18:43
Do you mean writing "TeX" or "LaTeX" or how latex renders them?
I think that was one of Knuth's few lapses... :)
I'd add the upright d's :D
(then again I'm not a fan of camel case in general...)
@Srivatsan: The rendered versions.
Hmmm, I don't like them but I have seen people commenting that they prefer seeing $\LaTeX$ than LaTeX. People here, on MSE.
18:45
Well, you won't see me using $\LaTeX$
Again: "To-may-to, to-mah-to..." :)
Po-tay-to, po-tah-to
I'm not quite sure which set uses the "po-tah-to" pronunciation...
One of my friends once remarked: "You call it potato, I call it tomato."
I found it hilarious; not sure if he created it though.
Couldn't do without either of them :)
18:49
On a different topic: sometimes I wonder who the Gravatar guys consulted for color advice. Somehow it looks like they didn't pick though their color list properly...
...such that some people end up with a puke-green or eye-melting-yellow Gravatar
Puke-green, ok. But I don't find eye-melting yellow anywhere.
t.b. had an exceedingly pastel yellow Gravatar at some point in the past...
That gives me the chance: whose gravatar do you guys like?
Random ones only?
or the Gravatars that are actual pics?
Let's nominate for the two categories separately.
QED
QED
18:59
I don't think "+" is the right operation
@QED: for what?
QED
QED
making pomatos
QED: Perhaps you misunderstood. Whatever operation you're thinking of, we just denote it by "+".
I think that "x" is better.
What do you get when you cross a tomato with a potato?
QED
QED
I'm against both "+" and "x"
oh when you put it that way... that's quite good
19:01
Ah, I like Asaf's suggestion better.
QED
QED
x works
Actually, Asaf's proposal is what botanists use...
Anyway, the random gravatar I find most attractive is Pete Clark's. I think the bright purple does it for me.
QED
QED
rainy day huh
19:03
It snowed a bit here. Why?
André's is a soothing blue.
I like Shai's pattern.
Oh, I see the appeal of Shai's. Could've been in a better color though.
That's a swastika.
19:05
(Again, I'm blaming the Gravatar guys, not the users. :) )
(like those arrows)
I like the patterns in Arturo's and Andre's actually.
Grigory's is a nice pattern. Would've been nice in a slightly darker green though.
Oh yes. Some of the colors are a bit too dull.
Okay, I gotta go. See you guys later!
19:09
Ciao!
Have a great time, @tb. Wish you happy birthday (slightly in advance).
I'd send a cake, but apparently icing fouls up Ethernet lines...
You can try ordering it online, J.M. =)
Eh, I don't have a credit card. :)
I like paying in cold hard cash.
Apparetly, tb left already. Never realized.
From the nonrandom gravatars, I like Mariano's and Douglas Stone's. Even Jonas has a simple, yet unique, gravatar.
19:15
Oh, you like that spiky polyhedron? :)
QED
QED
I have a math problem
Fire away, QED.
QED
QED
I'm reasonably good at the stuff I do (I got basic stuff down quite well), but I'm finding it impossible to get into something new
What's basic? What's advanced?
Hmpf. Apparently there was a grad shooting earlier today and the university won't open tomorrow :|
19:17
Oh, a soft problem... :)
@AsafKaragila Just to check, you meant cameras, right?
Hah. No.
Oh, so they went for target practice?
I see. The more interesting kind... involving guns?
Rockets, but yeah.
Hey, photography can be interesting... :)
19:19
I know. I used to do it for three years.
I even had a darkroom in my previous apartment for some time.
I don't see their point, J.M. :=)
(Reminds me of that seedy little photo shop I saw: "shoot your friends and frame your parents")
Asaf So you have university open on Sundays?
Israel is a Jewish country, so Saturday is the day off and the week starts on Sunday.
QED
QED
basic stuff like induction proofs and real analysis of sequences
19:22
Right, the Sabbath is the only "no work" time.
Yes, I know Saturday is a day off, but I assumed Sunday too will be off. (We work only 5 days a week here...)
QED
QED
I think it might just be that I don't have maths library access
Friday is usually a day off, or at best a half-day.
@QED How far away is the nearest university library?
Oh, I didn't know that.
QED
QED
19:23
it's not so much the distance as the cost
You have to pay 70 pounds to become a borrower
Wow, talk about steep education...
Doesn't your school have a library? And this is 70 pounds per month?
QED
QED
I'm not in school
I think it's a five months
It's going to be hard to learn from the Internet in this DMCA day and age (I was really lucky in those early days)...
...but certainly doable.
Asking questions here is a good start.
QED
QED
I wonder what to learn
19:25
That depends on what you want.
What suits your fancy?
QED
QED
That's a difficult question
And you want to read something because just because you are interested? Or is there some specific subject that you *should* read, for some reason?
You seen a lot of math and you don't know what to pick?
Set theory!
Study set theory.
QED
QED
there's no specific thing I should learn
19:30
No, you should learn set theory.
QED
QED
I guess I should learn about forcing
that's meant to be pretty cool
Quite!
It is pretty awesome.
@Asaf: Clearly you're the set theory pimp... :P
Obviously.
@JM ...and a successful one at that. =)
19:34
Im back
I am going to get me some beer. I will see you folks later.
Hi Matt, Bye Asaf.
See you, Asaf.
I am having trouble understaning this problem: imgur.com/Zg7fv
The solutions there, but im not sure why
(not hw btw, just studying)
QED
QED
That does not make sense
19:38
N?
Right
Is N the normal vector to that curve?
Or is that curve the function N
N is a letter.
Notation ought to have been defined earlier...
(My girlfriend got dibs on the shower :P)
Women always have dibs on the shower...
19:42
Asaf: do you have a take on the problem i've posted?
@Matt: no really, you probably need to read your text backwards to answer your question. The "N" should have showed up before that.
@J.M.: yea, it def. hasn't though.
Ok people. I will take leave. I am too hungry right now... :)
Is it only in the US math is used as the plural form of math rather than maths
19:47
Bye QED.
cya Srivatsan
@QED Yes, Cohen died.
QED
QED
Something slightly less soft: Any idea how to discover Strassman's theorem?
Burrow deep into his brain?
QED
QED
:)
19:54
@JM: What does Didier mean by 31 minutes. in the comments?
(In his own words) ...an answer got accepted 31 minutes after the question was posted. This behaviour seems to be more and more common amongst certain MSE posters although it has some obvious drawbacks, to which I wish to draw attention. For example, some would-be answerers will be de facto unable to post answers until after one got accepted, if only for time zone reasons. (The present post is a good case to mention this because the accepted answer is pretty decent.)
I guess I should have kept on reading :D
Not sure why I posted that, you obviously must have seen that. =)
i.e. OP was too quick to accept. Impatience, again...
Ah.
@SrivatsanNarayanan I only posted because I did not see it :P

« first day (451 days earlier)      last day (4865 days later) »