@Ilya I don't know... :D.

@Jonas: coffee bar or coffee shop?

Coffee bar.

@JonasTeuwen no, thanks then :D

:D.

I still want to do some work later this evening, so I'll stick to the whisky...

there is a cool one on Markt with a view on the small channel

@JonasTeuwen I had no doubts

A coffee shop or bar?

@JonasTeuwen bar. I was once to coffee shop a year ago, but I do not see any reason to be there more often

@Ilya You mean Kaldi? I'm there.

@tb a silly question: are there chain homotopies of singular complexes not induced by homotopies of underlying spaces?

@JonasTeuwen I meant coffeecompany.nl on the corner of Markt, close to old Town Hall

@AlexeiAverchenko you forgot @ tb in the beginning ;)

:D

@Ilya Oh yeah, that one :-).

@JonasTeuwen that's mostly writing, but Maike is a really cool teacher

Okay, I'll subscribe to the course.

Did you check out the mastermath courses?

@JonasTeuwen yes

Will you take any of them?

@JonasTeuwen can i check these out?

Algebraic Geometry

@AlexeiAverchenko The courses? www.mastermath.nl

@AlexeiAverchenko mastermath.nl/courses

Oh, I know another Russian that took that course last year.

I thought he was quite good and he said it was a hard course, so... :-).

@AlexeiAverchenko well, sure. take the negative of a chain homotopy, for instance.

@JonasTeuwen well, let us try again ))

what are credit points? is that the new european currency? :D

@tb thanks!

@Ilya I've asked my advisor about the mathematical biology course, he looked like this at me: :'D.

@AlexeiAverchenko One year of study is 60 EC.

@AlexeiAverchenko yeah, 8000 EUR = 60 EC for non-EU member

fuuuuuuuuu

@AlexeiAverchenko but there are of course much better examples. Thing is: maps induced from the underlying spaces are rather rare, so you can often perturb a little and get something that cannot possibly induced from a map from spaces.

@AlexeiAverchenko ah, that's another fuuuu?

how can anyone muster up 8000 EUR? It's crazy

@Ilya Did you check out the Lie Groups course?

@AlexeiAverchenko Scholarships!

The voting here is just plain silly.

@JonasTeuwen What's that?

For EU students it is about 1700€,

@JonasTeuwen I know. that's how open to everybody it is

@AlexeiAverchenko Then some organisation like the EU gives you the money to do those studies 8-).

@tb Brr, yes it is.

@JonasTeuwen you cannot imagine, how hard it was to obtani even Erasmus Mundus in Russia comparing to EU

Did you get Erasmus Mundus?

I was studying in Sweden, so I didn't need to pay for the education

@JonasTeuwen let me guess, statement of purpose, proof of ingenuity and roll 15 or higher

though, many of my friends - much smarter than me were applying for E.M.

@Ilya You won't take the PDE course?

@JonasTeuwen no

and only few of them passed. While in Sweden I saw a lot of students from EU who came with E.M. scholarship and didn't know the definition of an integral

...and mark of the Satan

@Ilya Yes, that's sad.

@Alexei: there are campuses at Anzhero-Sudzhensk, Belovo, Novokuznetsk, Prokopievsk, and Yurga, right?

campuses of what? :)

@robjohn what are you talking about?

@Jonas that's rather frustrating than sad (

i doubt Prokopievsk has any campus of any kind at all, it's provincial even by Kemerovo standards (and those are low)

I don't like the attitude displayed here

@AlexeiAverchenko Kemerovo SU.

That's what they claim, perhaps they've exaggerated.

@tb Has he seen the answer?

@robjohn don't believe them ))

@JonasTeuwen must have. He asked several questions in the meantime.

@tb by who? Me?

Okay, maybe he forgot about this one. Once you click the inbox-thingie the number disappears.

@robjohn i don't really know :)

@JonasTeuwen why are you defending him? )

@JonasTeuwen after I wrote a comment (Ignoring two pings seems a bit much)? I hope the downvote will help...

@Ilya perhaps they have a tutor who lives there :-)

@AlexeiAverchenko I wouldn't dare to imagine how many campuses has volsu )

@Ilya I'm not defending him, I'm giving an alternative explanation.

@robjohn and seriously, that can be the case

But right, ignoring two pings is a bit odd.

oh, they have an English version

@Ilya A second master costs 18k :'(.

@Ilya Do you miss Russia?

I wonder, since you're so far away from home.

@JonasTeuwen no, especially in the last week.

@JonasTeuwen My friend who moved here from Russia, says that he does not miss it.

I'm happy that @Alex won't go to the protest, it would be hard for me to resist

@tb He's shown up... nothing. Oy.

Okay.

What the hell is infinite dimensional topology?

Exactly what it says on the tin? :)

@JM you know if you've got more rep than gowers on MO...

@JM They have infinite dimensional topology in a tin? cool!

@tb rep is not smth you can rely upon too much, ah?

@JM Hmm. I'm not sure what a basis would be in a general topological space...

@Ilya don't tell me, tell him

@Ilya Well, SE itself says it's a rough measurement...

@tb I meant that if you've got a lot of rep on MO that does not mean that you're a cool guy, that's it

@Ilya Oh, good. I have no rep on MO ;-)

and I won't tell it him because I don't care about him

I'm a very cool guy and I've got a low rep :(.

:-p to all of you (((

I don't have high rep on MO too, so... :D

Maybe there's hope for us...

poor JDH...

@Ilya why?

who's JDH?

mathoverflow.net/users

@robjohn This guy.

@JM Thanks! I was just looking at that.

@robjohn Is this the SE/MO-equivalent of asking who's Michael Jackson?

@tb Okay, so I'm ignorant...

@robjohn no, he just not so active on MSE now

Who is Arturo Magidin

@robjohn No, it just means you're not a set theorist.

@TheChaz well... repeating jokes?

What t.b. said. :)

Ah, I see that Igor Rivin is there. He was a grad student at Princeton while I was there.

btw, did JDH just change his (user)name? I was just stalking his MO profile the other day and thought it was more that just initials.

I don't remember if we were the same class or he was a year behind.

Christian Blatter often has cool arguments :-).

@TheChaz Are you sure you looked at the MO profile and not the SE profile?

I am not sure. That's probably what happened.

(That <=> "Looking at the SE profile"...)

@JonasTeuwen Agreed. The answer of his that I most vividly remember is the one on expressing $\min(a,b,c)$...

@JM Do you have a link?

Oof, that was a typo. Here it is.

@JM Whoah!

I should MSE stalk that guy!

I'll go now home

See you, Jonas.

@Jonas: just was going out to smoke. It's windy again, isn't it?

quite depressive outside, or in my head

@Ilya still enjoying your cigars and cognac?

If they don't work, what else will?

@tb no, that's for more optimistic cases

if you enjoy good instrumental music

@Ilya Oh, thanks, I'll listen to that later

@tb if you wish )

@Ilya Oh, I'm currently cooking

@tb Ilya's conjecture: at each moment of time at least one member of this chat room is cooking

Yeah, this happens from time to time, but I don't make a big fuss out of it, usually :)

for me, that should be just tasty - that the criteria, so I believe I understand you

@Ilya Oh, sure it should be tasty! That's the whole point of it. Life's too short for crappy food. Crappy anything really.

Agree

I'm a bit in mixed feelings

You only live once, and all that. ;)

@JM you never know

@Ilya You know. Whatever will be will be. As far as I'm concerned, now I don't remember having lived before :)

I suppose. :) But still, it makes sense to enjoy things, as if you won't be able to do them again afterwards...

@JM yeah, there is no reason to silly waste the time

While the sun hangs in the sky and the desert has sand

We'll keep on trying

@tb me too )

I'll never understand the appeal of the divisibility test for 7 and 13...

When I try it out by hand, I can do the division faster than trying to remember how to split digits.

Ok, it's time to leave. @tb: good luck with cooking and enjoy your tasty meal ) @JM good night

See you, Ilya.

bye, my two-letter-handle-friends )

bye Ilya!

@Ilya Yes, it will be more windy than yesterday according to the predictions!

I need help in figuring out a question, may I ask?

Sure, fire away.

If C.P (cost price) of 21 balls is equal to S.P (sale price) of 18 balls , then what will be Gain/Lost percentage?

I'm thinking about this: math.stackexchange.com/questions/89450/… Hmm.

@FreakEnum How do you compute that gain-loss ratio?

@JM by s.p - c.p if gain

@JonasTeuwen Yeah, interesting question. But as OP says, it's hard to search for unnamed stuff...

@FreakEnum What happens if you do that?

@JM That is why I'm thinking myself in terms of narrow convergence :-). I'm trying to find an application when there is a common Radon-Nikodym derivative but it can be quite pathological.

@JM But I am unable to calculate S.P. and C.P.

@FreakEnum Yes, so the problem is underdetermined, no?

@JM no

@FreakEnum Why do you say so? You seem to know what to do...

@JM 0_o

@JM I tried to solve it but answer is way above wrong :(

You understand what I meant by "underdetermined", yes?

@JM yes

What answer was expected, and what did you get?

@JM Do you really think I am here so that I get my homework solved by some else?

No, I'm just trying to help you see through this. Note that I never asked about homework...

Anyways Thanks @JM for help

This was a bizarre end of the discussion...

A bit abrupt, yes.

Well, I should be sleeping now. See you later, t.b., Jonas, and everybody else...

@JonasTeuwen well there's this but it doesn't look terribly exciting.

@JM good night, JM

@JM Good night.

@tb Yes, not really exciting.

My answer had came 15.xx% and the books answer is 16.xx%

anyone can confirm whose answer is right?

@JM you still awake?

@JonasTeuwen on the other hand, Lasserre is not just any guy... I must be missing something.

@tb can you just confirm the right answer?

15.5xxx%

@TheChaz: I'll let you take over :)

@TheChaz cool , that means my answer was right and book's answer is wrong :)

@TheChaz 0_o , how did you get that answer then?

I "averaged" 15.xx% and 16.xx%

@TheChaz :D , Why'd you average that?

I'M A TROLL. Sheesh!

lol

@tb Now your turn to confirm the answer :)

Woohoo, there was a harmonic analysis question :))).

Here!

My answers are unappreciated. I must be doing it wrong!

Should I give the complete argument before people will vote?

@jonas: did kolmogorov's example converge or diverge? (english "do" should be "due")

Diverge.

Divergent almost everywhere.

@JackSchmidt Thanks for the correction.

I think then your answer doesn't answer the question. The guy wanted a fourier series that converged to the wrong function, I think. Probably like the taylor series of exp(-1/x^2) converges to f(x)=0

This gives an $L^1$ function that has an almost everywhere divergent Fourier series.

I see.

Let's finish my food and correct my answer. Thanks @JackSchmidt.

no prob

@Jonas: Oh, I didn't see the discussion here before posting my comment.

I was too hasty in replying.

@Jonas: thanks for pointing me at Christian Blatter's answer. I have added one, too.

I have edited my answer.

@robjohn You have a badbox :-).

@JonasTeuwen Only for a second, it should be fixed now.

You looked at just the wrong time :-)

@robjohn Nice :-).

Does this now answer the question?

Let me prove that claim.

What is the best way to revise Mathematics ?

@Freak: I got 16 \frac{2}{3} so 16.xx% seems the right answer

@MaX, I can't help but wonder if you are really talking about Mathematics, or about characters written on a website...

@JonasTeuwen That was what I was about to suggest.

Hm I am preparing for a competitive exam .. so it's mathematics..

Ah. You mean review (which is an auxiliary synonym of "revise").

just wondering is it possible for any mathematician to remember every tiny details always ?

yeah I mean review

@MaX Is this from a multiple choice problem? Otherwise, why would you change the exact $16\frac{2}{3}$ to $16.xx$?

There are results that (arguably) MUST be memorized, and then some that you should be able to reproduce/derive on the spot.

@rob

"FreakEnum" asked the question. tb linked to it (starred --->)

@robjohn: I am not sure about that ... I just the question as linked by t.b

Yes one of my teacher says that memorization is good for competitive and according to him I should not even bother about proving .. but I don't like this approach :/

I am currently preparing for two Major competitive exam ... according to my teacher I don't need to prepare the whole syllabus but I really despise this approach

@TheChaz Ah. Sorry, I didn't recognize that from what is starred.

Do you have a digital copy of the syllabus?

@robjohn I have proved one of those claims, should I also prove the Cesaro-thingies?

One I don't have it's IIM CAT they don't publish the syllabus they just include the topics .. like Quantitative aptitude , date-interpretation and English ...

@Jonas: so you are showing that $M$ has measure $0$, not that it is the null set, right?

I thought that a null set was a subset of a set of measure 0?

If it has measure 0 it certainly is a null set, I'd say.

Am I doing things the hard way?

but the quantitative parts includes all sorts of number theory problems and combinotorics , and elementary but not so elementary algebra, geometry and arithmetic problem

The other one is all of the undegrad maths..

They are not?

@Jonas: why are $M_m := \{x : |f_n(x) - g(x)| \leq \varepsilon \text{ for all }n \geq m\}$ increasing? I don't think they are.

Why would they be?

The convergence is not monotonic at every point.

Gibbs phenomenon is a counterexample, I believe.

Hmm. Let me think.

what exactly is studied in this measure theory?

@Jonas: did you mean $M_m := \{x : |f_n(x) - g(x)| \geq \varepsilon \text{ for all }n \geq m\}$ instead?

oh, no...

but then I don't see how $\bigcup_mM_m=M$

It is not equal, the symmetric difference is a null set.

@MaX see the wikipedia page in brief it's the theory of volumina (a measure associates sort of an abstract volume to certain sets) and integration (the general theory of integration).

I messed up the direction yes. I took it from my notes I once made and adapted it a bit.

@JonasTeuwen and I missed the "for all $n\ge m$"

:-).

so they are increasing

I have the feeling that I'm making it unnecessarily complicated.

Sheesh. That was a long evening.

@t.b.:Cool, but what exactly is its application? and this is typically taught in Masters level or Phd level ?

I could also prove the $L^1$ convergence of the Cesàro means.

@AsafKaragila Do elaborate.

@MaX No, second or third year undergraduate.

@MaX Read this post of Terry Tao's.

My girlfriend fainted at the university today. We spent it in the ER waiting for her CT results and whatnot.

Not so much for applications.

@AsafKaragila And?

@Asaf That's very scary; she's alright, though?

@Jonas: the $M_m$ seem to be decreasing to me...

Meh. Let me think again.

@Jonas Teuwen: But we don't have this in our syllabus.. The syllabus of undergrad seems widely varied from country to country!

@Dylan Morelan:So this is pure mathematics ?

@robjohn I think I had the sign correct the first time :-).

And nothing. She's fine.

@MaX You can't do any analysis without measure theory.

@MaX Main applications are real analysis itself, and of course probability theory. It arises in every sufficiently advanced branch of analysis. It's certainly a branch of pure mathematics.

@DylanMoreland You think that's scary? She called to tell me about it when she was there already, and I was sure at first that she's joking when she asked if she's in the same city.

@MaX I wouldn't say that. I just meant to say that Terry's post won't tell you a lot about the applications.

@MaX And I certainly don't know about them. Definitely people PDEs need this stuff and that's a very practical area of mathematics. And in measure theory course I took there were economists, engineers, and even people from the business school who didn't know what compactness was.

@t.b:Real analysis is not applied math I guess ? .. I haven't studied it formally in my university..

No real analysis, no measure theory? Wth!?

I don't think it was so fun for them. But people in their departments had clearly told them that they needed this knowledge.

@Jonas Teuwen:I am a C.S Honors undegrad student ... so I guess.

Another example: any sophisticated sort of probability will need this language, and probability is certainly practical.

@MaX I'm a bit wary of this classification into pure and applied maths, but yes, real analysis (the theory of functions and spaces of functions) would be pure maths in any reasonable classification system. Be that as it may, people doing applied stuff (numerical analysis, simulations) certainly do need real analysis as well. It's of fundamental importance to everything that isn't discrete maths, or abstract algebra, I'd say.

@Jonas: Let's break from that for a second:M_m := \{x : |f_n(x) - g(x)| \leqslant \varepsilon \text{ for all $n \geq m$}\} works in displaystyle, but not inline. It is better to use M_m := \{x : |f_n(x) - g(x)| \leqslant \varepsilon \text{ for all }n \geq m\}

Don't embed $...$ inside of a $\LaTeX$ construct if possible.

And this leads you into dynamics, stochastics, ...

@Dylan: We have probability theory last year but it wasn't much deep.

@Jonas: Now, back to the other: $M_m := \{x : |f_n(x) - g(x)| \leqslant \varepsilon \text{ for all }n \geq m\}$ is increasing, but what is its relation to $M$?

@robjohn Let me first fix the displays.

@t.b.:I had numerical analysis, and I wasn't taught measure theory or real analysis, we mostly have to made algorithms that work and write proofs and derive some results.. like that ..

Hello everyone

Hi

Hello Jason

@Asaf She didn't know where she was?

Could someone please take a look here and see if my drawing makes any sense or am I missing something in the answer