Mathematics - 2011-10-24 (page 3 of 3)

t.b.

4:03 PM

@Jonas: a question for you

Jonas Teuwen

@tb Thanks!

Asaf Karagila

@tb I got this...

But to be more accurate, I don't.

t.b.

huh?

Asaf Karagila

I actually knew the answer to that once. :-)

t.b.

One could just answer: Right.

Gortaur

4:06 PM

@tb he is simply jealous

@AsafKaragila sorry, once = ones?

Asaf Karagila

Nope. Once = once.

Once upon a time there was a Koenig that knew some answers to non-set theory stuff. He forgot them in time, and now he got no sound on his linux. The end.

2

J. M.

Not a fairy tale that kids'll like...

Gortaur

it depends, it depends

Asaf Karagila

Screw the kids.

J. M.

That's not legal in most countries...

Gortaur

4:09 PM

what does it mean, btw?

Asaf Karagila

I meant with a screw driver, mount them on the door and stuff.

Gortaur

ok

J. M.

Well, that too...

Asaf Karagila

You might need some nine inch screws for that, though :P

J. M.

(Okay, we've carried the joke too far... ;) )

t.b.

4:10 PM

Hm. What's taking him (Jonas) so long?

Gortaur

he never comes to a lunch, what can you expect

t.b.

Is it just me or is there a huge inflation of starred messages?

@Gortaur Probably he fell asleep...

Asaf Karagila

Yeah, which explains how three people got the Outspoken badge ;-)

Gortaur

maybe, it's SO sleepy here

@tb dots matter? )

t.b.

@Gortaur I'm always dotting my i's, unless I'm writing in Turkish

Jonas Teuwen

4:13 PM

@tb I'm messing with Mercurial. I will type up an answer in a few minutes.

Gortaur

@tb or you're using inclusions

J. M.

@Gortaur: When I have to put hats on my i's or j's, I don't use the ones with dots...

t.b.

But then I'm writing iotas, not i's...

J. M.

(i.e. \imath and \jmath)

Gortaur

@tb that's probably just because TeX is restrictive in typing i without a dot

dot my i!

t.b.

4:15 PM

Dot my ı

Gortaur

sounds like curse

dot my |

!

t.b.

That's not an ı, that's an |

nonsense

Gortaur

one more cigar

and home, sweet home

J. M.

The pipe is a different thing from the dotless i. ;)

Gortaur

salmon at the dinner

J. M.

4:17 PM

smoked?

Gortaur

me - yes

salmon - no

Asaf Karagila

I hate fish.

Gortaur

:DDDD

J. M.

Why do you not like fish?

t.b.

@Gortaur: remember that one?

►

Asaf Karagila

4:18 PM

I have a sense of taste... :-)

Gortaur

@tb yeah ) but from that album I mostly love Welcome to the Machine

J. M.

Well, if all you eat is catfish for instance, you have a point in complaining about blandness...

Gortaur

oh! great, I will go, smoke a cigar and play some Pink Floyd on the grand piano

J. M.

Floyd on the piano. Excellent. Enjoy!

t.b.

Sounds like a great idea. Maybe a whisky to go along?

Oh no, you drink Cognac, I forgot.

Gortaur

4:20 PM

@tb I don't allowed to drink it in my university

J. M.

Snobbier than whiskey. :D

Gortaur

@JM to be honest, my first cigar was a present to me for a nice play

I couldn't afford them that time

J. M.

Then all the more! At least you're not the only one enjoying, if you're a good pianist indeed.

Gortaur

I'm to shy to agree )

see ya

t.b.

@JM he rejects that idea

Gortaur

4:22 PM

my meditation is coming

t.b.

@Gortaur: have fun!

Gortaur

@tb prepare. The Russian Has Come

OMG IT"S THE SAURON

@tb thank you

and the mean square

4:23 PM

@AlexeiAverchenko haha, so I'm more scary

nice, nice

Alexei Averchenko

i'll have to pull something evil on my ohn

J. M.

Alexei, can that girl there slay monsters by any chance?

Alexei Averchenko

ghm-ghm

use your aggressive feelings, boy

let he hate flow through you!

she can create them in her sleep

Haruhi Suzumiya

is the general name for a series of light novels written by Nagaru Tanigawa and illustrated by Noizi Ito which were subsequently adapted into other media. The story follows the title character Haruhi Suzumiya, a high school girl who can unconsciously change reality, and her strange antics with her school club, t

J. M.

On the other hand, melancholy is a monster of sorts...

Alexei Averchenko

that anime is great btw, on par with higurashi and madoka

t.b.

4:30 PM

@Alexei: I remember a thread where some user was wondering if there is something NSFW is going on on your gravatar :)

(the thread is deleted now)

Alexei Averchenko

something what? :)

where, on meta?

oh, btw

"The dual of the flabby is the bar" - really? :D

t.b.

tss

Alexei Averchenko

James A. Schafer, The Dual of the Flabby is the Bar

J. M.

A certain MO thread comes to mind...

Alexei Averchenko

google.com/…

t.b.

4:36 PM

got it

J. M.

Yeah.

Alexei Averchenko

i understand it were 60s, but come on!

t.b.

@JM: you're starting to seriously annoy me, you know :DDD

always better links, quicker, and whatever :s

Alexei Averchenko

are these things still called a flabby and a bar?

t.b.

flabby resolutions, bar resolutions, sure

Alexei Averchenko

4:39 PM

WHY?

J. M.

@t.b. I ain't even tryin' to compete! :D

t.b.

come on! rub it in! that only makes it worse!

J. M.

I can't win...

@AlexeiAverchenko You know the answer: BECAUSE!

Alexei Averchenko

almost as good as the classic: www-math.mit.edu/~ptingley/lecturenotes/Kauffman_vs_sl2.pdf

J. M.

(more seriously, if you could think of a better name, maybe you can use that in your papers.)

Alexei Averchenko

4:42 PM

i don't mean disrespect by any means, no sir :)

J. M.

That article I know is already in that MO thread... :)

t.b.

@Alexei: It's from history (group cohomology). People used to use the standard simplicial models of EG and BG used to write [g_0|...|g_n] for the simplices of one of them to distinguish them from those of the other. That's why bar resolution.

Jonas Teuwen

@tb I have posted an answer to that question. It might be unnecessarily complex.

t.b.

Clarkson?

@Jonas: that's the standard argument.

Jonas Teuwen

Yes, but maybe it is easier in this particular case.

(on [0,1]).

t.b.

4:47 PM

Ah, you mean that you can exploit an inclusion of Lp into L^q and play the trick that works for L^2? Dont think so.

Jonas Teuwen

Yes, I was wondering if that was possible...

Alexei Averchenko

i think i'll actually post this article in that MO thread

J. M.

This is it for me today. I need to hit the sack. Later!

Alexei Averchenko

i don't have anywhere lower to sink in terms of rep there :)

bye

t.b.

@JM Later!

Alexei Averchenko

4:53 PM

awww, that thread is closed now :(

t.b.

@Alexei: tough luck. The flabby stuff comes from sheaves by the way. You have all sorts of sheaves flabby, soft, etc.

But the stuff is now encompassed in the theory of monads (=triples)

See Weibel, Ch. 8, for example.

Jonas Teuwen

6:49 PM

Great. Two correct answers today.

robjohn

7:01 PM

@Jonas: I am not even sure if the converse was a part of the question, but you are probably right about the level of detail needed.

Jonas Teuwen

Oh, that other part seemed easier, so I skipped it.

robjohn

But that was the part the OP was asking about, at least it seemed to me.

Jonas Teuwen

Oh. Oh well.

Gortaur

ash nazg trum pum pum

robjohn

I err on the side of more detail. If the reader were doing well reading Stein, they wouldn't need help at all. Seeing as they needed help, I don't know how much help they might need. They could only get to the formula for a_n, so... :-)

@Gortaur Need a Black Speech refresher?

ash nazg gimbatul, or something like that

`Ash nazg durbatulûk, ash nazg gimbatul,`
`Ash nazg thrakatulûk agh burzum-ishi krimpatul.`

Gortaur

7:09 PM

dark lord had dinner. dark lord is sleepy

robjohn

quotes don't work on multiple lines :-(

It is getting on in the evening there.

It is just past noon here.

Gortaur

I'm from phone, so unfortunately i`m a bad dark lord to talk to

oppp

the emoticon of a cyclope with three tongues

robjohn

I'll remember to stay clear.

don't want to be licked with three tongues by someone with no depth perception.

8-)

Gortaur

no way. he is my pet

I'm reading about vanile.... girls

the love to drink coffee, staring at rain and thinking about him

Asaf Karagila

Here's a problem... I am missing /dev/dsp altogether!!! :\

Gortaur

7:21 PM

moi also loves staring at rain, but I don't like coffee anymore. I'm not vanile nuff

Asaf Karagila

Oh, if you don't use OSS then you don't need those... I'm still boned :\

Gortaur

@Asaf think about the life and the sky. it rains somewhere now

robjohn

@AsafKaragila I don't have /dev/dsp either. What is it supposed to be for?

Asaf Karagila

Are you on linux? What distro? Which sound system are you using?

robjohn

Ah, I am on Unix.

Jonas Teuwen

7:29 PM

@AsafKaragila sudo touch /dev/dsp.

Asaf Karagila

@Jonas: ALSA doesn't use /dev/dsp so there shouldn't be one.

Jonas Teuwen

7:42 PM

Easy analysis is easy.

Asaf Karagila

By definition it is.

Jonas Teuwen

As in: analysis is by definition easy or easy analysis is by definition easy?

Asaf Karagila

Latter.

Benjamin Lim

8:46 PM

@JackSchmidt Sorry I was thinking right, the map is R[x] -> C that sends f(x) -> f(i). If one says that kernel is the ideal generated by the polynomial (x-i), that would not be right for i is not a real number. However if one says that it is generated by (x^2 + 1), then I think this would be right.

@robjohn Did you have something to ask me about?

Jack Schmidt

@BenjaminLim: yup, exactly

Benjamin Lim

I think that the proof that (x² + 1) is the kernel is straight forward, clearly x^2 + 1 is in the kernel

Jack Schmidt

(so far so good)

Benjamin Lim

However say I wanted to show the reverse inclusion

we evaluate a polynomial at i

Ok, suppose g were to be any other polynomial in the kernel

By the division algorithm we can write g = pq + r, where p = x^2 + 1, q some polynomial in R[x] and 0 \leq deg r \leq 1

If deg r = 0 we are done, otherwise since g is in the kernel and p is in it too, pq would be too for the kernel is an ideal

so g - pq = r is in the kernel too

viz if r ax + b, a(i) + b = 0

equating real and imaginary parts gives a = b = 0

so g is a multiple of the polynomial p, hence g \in (x^2 + 1)

robjohn

@BenjaminLim You had asked a question earlier, and did not reply to someone who asked you about it. I did not see you had left, and so I called out. :-)

But you seem to have gotten everything straightened away.

Benjamin Lim

9:01 PM

Thanks, anyway that question was not correctly posed, I have reposed it again and am chatting with this person now.

Yeah I woke up this morning saying this is how you do it

Jack Schmidt

@BenjaminLim: yup, exactly. that is the proof.

Benjamin Lim

@JackSchmidt Thanks.

I may have to leave now, I shall return in a few hours, thanks for your guidance.

Yeah, Jack! :-)

no problem

Okay it works.

9:16 PM

@AsafKaragila good :-) What works?

Asaf Karagila

The sound.

robjohn

Ah. Now music can soothe you?

Asaf Karagila

Yeah. Or I can watch funny youtube stuff.

robjohn

Very good. That is very important.

Asaf Karagila

Yeah.

robjohn

9:21 PM

What is the lowest positive integer multiple of 7 that is also a power of 2?

and they say that the quality of questions is not what it used to be...

2^{-\infty} of course.

Asaf Karagila

0?

robjohn

oops, they did say positive integer multiple.

anon

7. They said integer multiple of 7, but they didn't say integer power of 2. :)

Asaf Karagila

Nice.

robjohn

9:36 PM

@anon yes.

Asaf Karagila

9:50 PM

I don't get why the "Can I use my powers for good?" question got 150 votes...

Jack Schmidt

"not good" is finance instead of military is a neat reflection on the times

t.b.

10:21 PM

@robjohn who says that?

hi all

robjohn

It was sort of a rhetorical question, intended to mean the previous question was lower quality.

Asaf Karagila

I think I'll go get me some beer.

Salutations!

Oh boy, how I am not waiting for the semester to begin :\

Jonas Teuwen

Didn't it start already?

Asaf Karagila

We start on Sunday.

Jonas Teuwen

Cool.

Asaf Karagila

10:51 PM

@rob: How was the "axiom of choice lecture" last night?

Mike Spivey

Greetings all. @t.b.: Wanted to follow up on our meta discussion about the integration-related tags. Do you know if "integration" is supposed to be the "indefinite-integration" tag corresponding to the "definite-integration" tag, as per Bill's suggestion?

Asaf Karagila

Howdy Mike.

Mike Spivey

Hey, Asaf. Per your question above... the "Can I use my powers for good?" question went viral. It was listed for a while on the "hot questions" list for the entire SE network, and so a lot of people who don't normally use math.SE read it, upvoted it, and chimed in.

robjohn

@AsafKaragila You mean the jazz concert?

Asaf Karagila

Yeah, that lecture about the axiom of choice... :P

t.b.

11:01 PM

@Mike: I don't know, the description for integral is Questions on the evaluation of definite and indefinite integrals and the one for integration is All aspects of integration, including the definition of the integral and computing indefinite integrals (antiderivatives).

robjohn

It was very good. It was more of a big band sort of thing, with some jazz influences.

Asaf Karagila

Big bands??

t.b.

So it doesn't seem like Bill's suggestion was implemented completely

Asaf Karagila

Did you take the time machine to 1947?

robjohn

@AsafKaragila yes, that is exactly what we did :p

Asaf Karagila

11:03 PM

Good thing you did not assassinate Stalin and Goedel while you were at it.

Mike Spivey

@t.b.: Yeah, I read that, too, which didn't help me much. I was wondering if you remembered some discussion on meta about the introduction of those two tags? I'm also wondering if "definite-integration" and "integration" are to "integral" what "abstract-algebra" and "algebra-precalculus" are to "algebra."

robjohn

I was tempted.

Asaf Karagila

If I ever have a time machine, I am going back 10 minutes before having the time machine and killing my "younger" self.

That way I will trap the universe in a paradox-loop lasting only a few short minutes! Muhahaha.

Mike Spivey

In other words, maybe some critical subset of the community really wants the "integral" tag to be split into the other two, but there are too many questions already tagged "integral" for that to be feasible at this point.

And @robjohn: What's up with the new logo image? :)

robjohn

It's the mean square

Mike Spivey

11:07 PM

Any relation to the root mean square?

robjohn

they are cousins

once or twice removed.

Asaf Karagila

The root mean square is a tough sysadmin!

t.b.

I really don't know. I linked to the threads I can remember at the moment but I didn't read them thoroughly. Anyway, I agree with you that it is a bit of a mess, and the tagging system's design doesn't allow for easy organization of the tags retroactively, mostly because the higher ups are so strongly opposed to a hierarchical system that would allow such specializations to be implemented. Also, we can't retag without bumping, so it is likely to stay that way.

robjohn

but he spends all his time playing sudo ku

Asaf Karagila

As a sysadmin should!

t.b.

11:10 PM

I don't know how strongly the community feels about this matter.

But probably your last message sums the situation up. I don't feel strongly in either direction.

robjohn

If no one cares enough to change, leave it be.

Mike Spivey

@t.b.: Thanks for your thoughts. I think you're right. The tag system is such a mess in places. Well, I'll wait to see if anyone else comments on my post about the integration tags, and then I'll decide if I want to try to improve things. A lot of people don't read the "Tag Merging and Synonyms" question anymore, though, I think; there are just already too many answers to it.

Asaf Karagila

+1 on that last comment.

Mike Spivey

@robjohn: Yeah, there's that, too.

t.b.

@Mike: I think Willie should remember because he was involved in that thread. So I'd wait until he finds the time to comment on your suggestion on meta but he seems pretty busy recently. I didn't answer to your query there because I don't have much to say.

Jonas Teuwen

11:17 PM

Good night guys!

t.b.

@Jonas: good night

robjohn

@JonasTeuwen have a good night!

t.b.

@Srivatsan: in case you want to follow up on your literature question, I'd have time now.

Asaf Karagila

I'm bored. Someone bring up the axiom of choice :P

Interesting how that {0,1} 1+1=0 question developed. From -3 it has -1 and so on.

t.b.

@Asaf: Apparently some people are of the opinion that good answers do make a good question...

robjohn

11:29 PM

who cares about the question? upvote my answers ;-)

Asaf Karagila

I actually thought about deleting my answer, but then it got accepted :P

Not that I complain about that, but I think I can improve that answer. I'll give it a few days before revising it.

Mike Spivey

@t.b.: I think sometimes people upvote the question to signal to people on the main page that there's an answer worth reading there.

4

Since the main page only shows upvotes on the question.

t.b.

@Mike: Interesting. That idea never occurred to me.

robjohn

@Mike: almost put you to 16000

Mike Spivey

@t.b.: I only say that because several times I've seen questions get zero or only a few upvotes at first - but then after someone posted a nice answer people started upvoting the question.

@robjohn: Thanks! Maybe I should drop into chat more often! ;)-

t.b.

11:36 PM

@Mike: that observation was precisely my motivation for my comment to Asaf.

robjohn

@MikeSpivey It had nothing to do with the chat, actually. I was just looking at some old answers and saw yours and that it needed another upvote.

t.b.

@JM: good morning!

Asaf Karagila

Howdy J.M.

robjohn

Of course, if the question weren't asked, the answer wouldn't have been given. Sometimes the inspiration for a good answer deserves a reward.

Mike Spivey

@robjohn: Actually, I was over 16K earlier today, but then I requested that an incorrect but old (over a year) answer be deleted, and that dropped me back below 16K. Whatever the reason for the upvote, thanks. :)

robjohn

11:38 PM

Even if the question doesn't really change the answer. It's a social thing.

J. M.

Good morning to you two, t.b. and Asaf.

Mike Spivey

@t.b.: Well, I may have drawn a wrong conclusion from our mutual observation, but there it is.

@J.M.: Good morning, as well.

Although it's late afternoon here.

robjohn

@JM good morning to you!

J. M.

Hey, Mike and Rob. :)

robjohn

we be coasting... west coasting.

Mike Spivey

11:39 PM

Yay, Pacific time zone! :)

robjohn

where it's 4:40 PM

Asaf Karagila

I hate AM/PM.

robjohn

just over a week of PDT

then back to PST on Nov 6

(-7) to (-8)

16 people in the chatroom! WOW

Mike Spivey

@robjohn: Just looked at that answer you upvoted. I had forgotten that you were the other person to answer that question.

J. M.

@tb The integral tag was a tag I created when I asked one of my first questions here. I'm alright if it is indeed felt that a split into the definite and indefinite sorts is needed, but I'm not actively campaigning for a split either.

@robjohn That has to be a record...

robjohn

11:44 PM

@MikeSpivey that was a long time ago, I was even more newbie than I am now.

long time for me, at least.

Mike Spivey

@robjohn: The other thing that did was that now "combinatorics" is tied with "probability" for the tag that I have the most upvotes in. For about a year "probability" was my highest upvoted tag.

t.b.

@Mike: It would be very intersting to know more about the reasons why people vote. There seem to be so many different motivations/thoughts that go into this, and often enough they seem to interfere. I thought about opening a meta thread on that several times already, but I always hesitated for fear of the outcome.

robjohn

@Mike: Mine is by far calculus, but I had thought I had answered more questions in other topics. I guess it is about how things are tied together and what multiple tags are there.

Mike Spivey

@t.b.: There have been some discussions on meta, I think - mostly around complaints about good answers to technical questions not getting enough upvotes and clever answers to easy questions getting too many. It might be interesting to see what such a meta question would produce - although it might be scary, too. :)

Asaf Karagila

@robjohn Don't vote to him. I am trying to gain on him in terms of reputation, help me instead! :-D

robjohn

11:49 PM

Does real-analysis tie to calculus in any way?

J. M.

The likelihood of being both scary and interesting is high, I feel. :)

@robjohn As a tag, or the actual subject?

robjohn

Ah, never mind. I was misreading Mike's message.

t.b.

@JM thanks for that info. The discussion was sparked by Mike's latest entry on the tag merging/synonyms thread.

Mike Spivey

@Asaf: What you should do is convince your friends to sign up and post questions on the axiom of choice. Since I have zero chance of answering them, you'll start outpacing me more and more. :-D

robjohn

I have to get ready to go out to the Griffith Observatory tonight. Feed the dog, walk the dog and then drive out there.

J. M.

11:51 PM

Oh, I haven't checked meta yet. Main has a long queue of questions... :)

robjohn

So I'll see you when I get back. :-)

Asaf Karagila

@MikeSpivey I can hardly convince my friends to sign up. They also tend to ask me in person and since Israelis usually talk with their entire body it's easier to explain in real life instead.

Also, most of the folks around here don't really care about AC issues.

robjohn

@Asaf, I have some bad news for you...

J. M.

"talk with their entire body" - how do you describe infinite sets with your entire body? :)

robjohn

;-D

Asaf Karagila

11:53 PM

@robjohn ZF is inconsistent? D:

@JM You do this thing with your arms.

Mike Spivey

@robjohn: Griffith Observatory... my wife has been meaning to take me there for 10 years now (her parents live in LA), but it was closed for a while. I'm sure I'll make it some day.

Later, dudes!

Later!

WAAAIIITTT

@robjohn: Later!

11:54 PM

Later!

Asaf Karagila