Mathematics - 2011-12-10 (page 1 of 5)

t.b.

00:05

@Srivatsan better?

Srivatsan

@tb what did you do? :)

t.b.

@Srivatsan Nothing. Just this:

Srivatsan

Aw, nice. [except for the right hand border; should be cropped a bit more.]

Instead of this +1/-3 routine, Michael could have downvoted some answer =)

@tb That looks good, thanks.

Zhen Lin

00:52

Hmmm... I thought the right notion of "exact" for semisimplicial complexes would be to have each fork a coequaliser, but I'm having trouble showing that, say, the Čech nerve of a cover is exact (as it ought to be, since it's a simplicial resolution)...

Srivatsan

What on earth happened to my comment? =/

I could swear I replied to Qiaochu's comment. Oh well...

MaX

Hey Srivastan!

Srivatsan

Hi MaX

MaX

How are you today ?

Srivatsan

and it's srivaTSan =)

MaX

00:58

oops srivatsan*

Srivatsan

Well, I am doing good. How about you?

MaX

I am doing good too :) btw you too Indian right ?

Srivatsan

Yes, I am.

MaX

So not sleeping ?

6:29 am!

Srivatsan

Oh, oops. I am not staying in India right now. I live in Pittsburgh where the time is 8pm.

MaX

01:00

Oh! Job/Phd ?

Srivatsan

@MaX Now that you brought it up, what about you? You ain't sleeping?

@MaX Ph.D. in computer science.

MaX

I wake up to study :D

Srivatsan

Ooh, alright ;)

MaX

Cool man!! you IIT-ian ?

Srivatsan

@MaX Yes, graduated from IIT Madras 2.x years back.

MaX

01:02

I figured that out when you answered one of problem so fast :D

Srivatsan

What do you do? Are you an undergrad?

MaX

Yes CS undergrad!

Srivatsan

@MaX And where do you go for college?

[And you are Deb, right? Is it ok to use the name?]

MaX

@Srivatsan:I am Bsc CS(H) Burdwan university

Yes sure I am Debanjan :)

Srivatsan

Well, cool, man. How did you get introduced to mse?

MaX

01:06

I was a member of stackoverflow and then here

and you?

Srivatsan

Aw, nice.

I joined MO first. I was kind of a misfit there. I then came here. I don't remember how I came to know of MO.

MaX

Aw, great! btw you know sufficiently more maths than any normal CS undegrad isn't ?

Even for IIT-tians I guess..

I thought you were a Math phd :D

Srivatsan

@MaX Depends on what kind of math, and which kind of students you're looking at :)

MaX

Um I participated in SPOJ and topcoder very actively last year so students were quite good :)

Srivatsan

Since I work in theoretical cs, it's only fair to compare me with my peers. Compared against them, I perhaps know more of the traditional kind of math.

@MaX I tried my hand at them when I was at undergrad. I didn't enjoy them very much.

MaX

01:10

@Srivatsan: Oh why so ?Spoj kind of inspired me to learn maths more.

Or is it because you don't like application much?

Srivatsan

Yes, I did like spoj. Me and my friend -- we were a nice pair. He knew more on the programming part and I handled the math part better than him.

topcoder is way too competitive for me.

MaX

I really enjoyed SPOJ!! Too bad I can't do that anymore :(

Srivatsan

@MaX - why can't you do SPOJ?

MaX

Yes topcoder is .. it requires a different kind of devotion and through practice.

@Sri: because it sucks lots of time...

Srivatsan

@MaX Yes, I was too much of an amateur in that place.

@MaX =).

MaX

01:15

So you are a prodigy ? or just normal man with lots of practice ? :D

Srivatsan

@MaX I am not, by any stretch of imagination.

I don't even like prodigies. =) I am a normal man with some practice, some knowledge.

MaX

You are humble :)

Gigili

Prodigy on what? Mathematics?

Hello, BTW.

(Dead people are watching us)

Srivatsan

@MaX I don't know why you would think that, but no. There are no prodigies. :)

@Gigili Hey Gigili.

@Gigili - what does that mean?

MaX

@Srivatsan: :)

Hello Gigili!

Ilya is a Russian name isn't ?

@Sri

Srivatsan

01:20

Yes, I think it is.

Gigili

@Srivatsan Means, umm, never mind. =)

Srivatsan

@MaX I removed my comment because there seem to be too many Ilyas actually.

MaX

@Sri: Hm okay.

Gigili

@MaX: Didn't you find a solution to your statistics problem?

MaX

@Srivatsan: So how you become interested in maths? Olympiad training?

oh

which one ?

Gigili

01:23

Wait, I should find it.

MaX

@Gigili

Srivatsan

@MaX I didn't train properly, but I was in the national level thing. I couldn't clear that and attend IMO.

MaX

@Srivatsan: That's sad, but you are good :)

Gigili

@MaX This one.

(Sorry for double ping)

Srivatsan

@MaX Slightly =)

MaX

01:28

@Gigili:Oh yeah, one of my unaccepted questions ;) you both are right but tards' explanation seems expatiated.

@Srivatsan: Can you advice me about one thing?

Srivatsan

@MaX What about?

MaX

@Sri: Mathematics ofcourse

Srivatsan

@MaX Ok, go on.

Gigili

@MaX Yes, the other answer seems complete to me, I just didn't get some parts of it. I was just curious about the correct answer.

MaX

I am having some trouble in deciding an optima strategy to review, my subjects.. particularly for competitive exams, It seems like I am loosing grip over one thing when I am studying something else ..

Like say I am preparing for CAT along with other MSc entrances.. and the syllabus is varied

Srivatsan

01:34

@MaX How do you prepare for these?

MaX

For CAT I am under training in IMS

and for Msc entrances I am on my own along with my professor

Srivatsan

Right. Let me be straight up with you: I didn't prepare for any of these exams (except GRE).

MaX

GRE is almost like CAT and you prepared and cracked for IIT JEE! just wondering how you manage to revise?

Srivatsan

But your MSc entrances -- do they overlap with your normal syllabus or are they very different?

MaX

Syllabus is normal like same as undergrad CS along with high school level Math but some have undergrad level maths too say JNU

Srivatsan

01:38

Undergrad level math? That's surprising.

And which year are you in?

MaX

Final.

Srivatsan

Oh, ok. When are the exams? :)

MaX

The syllabuses are really varied from university to university.

CAT is next November probably.

Other would be probably in mid may

Srivatsan

Ok, how long do people prepare for CAT?

MaX

I started from last june

Srivatsan

01:41

@MaX No, I am wondering how much preps is recommended?

MaX

@Srivatsan:I don't get your question, my instructor says no preparation is enough in CAT preparation :)

Srivatsan

So you prepare from past year papers, no?

MaX

Yes

oh No .. not now .. I am on IMS modules only

Concept building phase!

Srivatsan

@MaX Ok, can you give me an idea of the breadth of the syllabus needed for the MSc exams?

MaX

Hm sure!

I will be writing this exam next year, you can find the syllabus here

Srivatsan

01:46

Ok, let's run through this list. What all things are you confident about? What needs more review?

MaX

@Sri I edited the link to a general one that includes every thing I need to review before the exams

@Sri: You can see the CAT syllabus is a subset of this :/

Srivatsan

@MaX Which parts do you feel are you weak in?

MaX

@Srivatsan: Geometry precisely but this exams set such papers you can never know which one they will set easy and which one will be hard.

So I guess I have to prepared equally in all parts ?

or would you advice in particular strength?

Srivatsan

@MaX Not sure. I feel you should reinforce your weak aspects first.

MaX

hm. but the problem is I tend to loose my strong parts when I don't review them at regular interval... :/

Srivatsan

01:56

@MaX Do you feel you do not know the concepts or you're unable to apply what you know properly?

robjohn

@tb Mine a couple of days ago:

Srivatsan

@robjohn Close enough, but definitely less impressive, robjohn. =)

robjohn

Wait, that was supposed to be 12,345

Srivatsan

@robjohn Yes, you are 12545 right now.

robjohn

Wrong screen shot :-)

MaX

01:58

@Srivatsan:It depends on the problem, and depends on if had solved a similar type .. I am good in connecting the dots but sometime I just can't see the solution even if the knew the concept and this later happens mostly while dealing with geometry problems

robjohn

That's the right screen shot :-)

That was on Dec 7 at 3 AM

Nov 29 at 0:43, by robjohn

Ooh, I hope that I hit 1000 more rep exactly.

That was at 11345 :-)

Srivatsan

@robjohn Cool.

@robjohn I remember that. That's why I pinged you saying Michael's close. He was 12346 at that time.

robjohn

1 off, was that his avatar that was shown at 12345 a while back?

Srivatsan

But good job, climbing by a 1000 rep in like 7 days.

@robjohn No, mysteriously, he then received a (question) upvote and 3 downvotes =)

robjohn

I see that Michael has a 3 -2 votes so that a 5 vote would bring him to 12345 :-)

Srivatsan

02:05

Yes. +5-3 \cdot 2 = -1.

robjohn

Mine just happened like that, though I think someone may have upvoted one of my answers to make it happen faster.

Srivatsan

:-)

Wonder if I will attain 12345.

robjohn

@Srivatsan Just like you mysteriously got 3 upvotes at the last minute the other day ;-)

MaX

@Srivatsan:what's your current rep?

Srivatsan

@robjohn Yes, these coincidences are eerie, no?

robjohn

02:09

@Srivatsan quite.

Srivatsan

@MaX 10,740.

MaX

Cool!

robjohn

off to the park to walk the dog. bbl

Srivatsan

♪ Jingle Bell Rock

J. M.

@ZhenLin "Kosher" is the word you intended to use, I suppose... :)

MaX

02:16

@Sri: You prepared GRE on your own ?

Zhen Lin

@JM: No... I mean haram.

Srivatsan

@JM No, I think he meant haram. haram means prohibited, halal means it's ok.

@MaX Yes. Me versus my Barrons :)

J. M.

Okay, "not kosher". Read too quick.

MaX

@Sri: Cool! YOu cracked it right ? :)

Zhen Lin

Well, actually, I meant not halal.

MaX

02:18

'kosher' is a word of which language?

Srivatsan

@MaX It didn't quite matter. My scores were on average. Many of my friends got more than me, many got less. But it wasn't too bad and the score is not too important, so I can get away.

@ZhenLin So these two words are not mutually exclusive and exhaustive?

MaX

@Sri:Good to know that :)

Zhen Lin

@Srivatsan: Which two words? Halal and haram are essentially antonyms, but halal and kosher are not synonyms.

Srivatsan

@ZhenLin Halal and haram.

MaX

Halal and Haram is urdu I believe..

Srivatsan

02:21

@MaX Originally Arabic, perhaps.

Zhen Lin

They're originally Arabic words (as you'd expect).

MaX

Hm.

I like Arabic songs, however I don't understand the lyrics

Zhen Lin

Arabic has an interesting sound, but I probably couldn't ever pronounce it...

J. M.

Ech, long transcript.

Srivatsan

@JM You're welcome, JM =)

J. M.

02:24

I just finished reading it. :) So you were talking about Euler-Maclaurin for a while with rob, Sri...

Srivatsan

@JM One of these days, I am going to write a script that automatically uploads comments every 5 seconds, just to keep you busy in the morning. =)

@JM Oh, yes. Kind of inconclusive.

J. M.

@Srivatsan Bastard. :P :D

Srivatsan

@JM The main conclusion I could draw from the discussion is that I do not understand Euler-Maclaurin enough. =)

J. M.

But seriously, they really should be adding TeX now with all the chat traffic.

Srivatsan

@JM TeX begets traffic.

J. M.

02:27

(Of course, the bookmarklet by rob, Zhen, and everybody else is great!)

MaX

Alright time for classes.. see you guys soon :)

Srivatsan

@JM Yes, that works so handsomely that it's easy to forget the days of no TeX.

@MaX see you, MaX.

MaX

@Sri:Take care :)

Srivatsan

You too.

J. M.

See you MaX.

Srivatsan

02:30

Do you want to do the honors, @JM? math.stackexchange.com/questions/tagged/inversion

J. M.

Done. Now, we wait two days...

Zhen Lin

math.stackexchange.com/questions/90083/… – close as duplicate please?

J. M.

One juror and one executioner still needed.

Pfft, I'm being called out. Catch y'all later.

Srivatsan

@JM Thanks, JM.

Srivatsan

02:47

Can anyone figure out why the two $\phi$'s look different in this wikipedia page: en.wikipedia.org/wiki/Banach_limit?

Zhen Lin

Some are being rendered in LaTeX and some in plain HTML.

Srivatsan

@ZhenLin Oh, thanks.

Have you ever edited a wikipedia page?

Zhen Lin

Yes.

Srivatsan

Ok. Was just curious.

Potato

03:22

Any experienced putnam people here?

Srivatsan

04:22

I don't know if it's just an illusion or whether my proof really gets much better every time I rewrite it. ;)

Perhaps it actually gets worse... who can tell?

Skullpatrol

06:15

@Srivatsan May I interrupt you with an inquiry?

Srivatsan

@Skullpatrol Yes.

Skullpatrol

Is it possible to find out which questions have the highest up votes?

also can this be done for answers?

Srivatsan

@Skullpatrol One second.

Check this: math.stackexchange.com/questions?sort=votes.

I am not sure about the answers.

Skullpatrol

@Srivatsan I feel so stupid for not seeing the "votes" link, but I'm asking this so I can find what it takes to ask a "good" question ... do you know who I can ask to find the highest voted answer so I can find what it takes to give a "good" answer?

Srivatsan

@Skullpatrol There should be some SE query for this. You can ask JM.

Skullpatrol

06:29

@Srivatsan Thanks for the information

Srivatsan

You might be interested in this meta post: meta.math.stackexchange.com/questions/1743.

Skullpatrol

@Srivatsan That answers my inquiry completely, thanks again.

Srivatsan

You're welcome.

Rajesh D

07:30

hi

QED

hi

Rajesh D

i have a question which is an inquiry...do not need any proof...just for knowledge

Is there any difference in the cardinality of set of all points inside a circle and the set of all points on its circumference ?

@sri @QED

Srivatsan

@RajeshD The two sets have equal cardinality: equal to the cardinality of the real numbers.

Rajesh D

@Sri : thanks for the answer

but how to distinguish these two sets in some way

I am having Bertrand's paradox in mind

Srivatsan

Yes, distinguishing them is an important problem. There are many ways to do distinguish them.

@RajeshD What's that? Do you mean Russell's paradox?

Rajesh D

07:38

yes about probability

Bertrand paradox (probability)

The Bertrand paradox is a problem within the classical interpretation of probability theory. Joseph Bertrand introduced it in his work Calcul des probabilités (1888) as an example to show that probabilities may not be well defined if the mechanism or method that produces the random variable is not clearly defined. Bertrand's formulation of the problem The Bertrand paradox goes as follows: Consider an equilateral triangle inscribed in a circle. Suppose a chord of the circle is chosen at random. What is the probability that the chord is longer than a side of the triangle? Bertrand gave thre...

Srivatsan

@RajeshD What's this got to do with your question?

Rajesh D

In one solution to the B's paradox, we choose two points on an arc to pick a chord, where as in other solution we choose based on area

It just seems to me....i am not clear on how it is related...just have doubt in mind

Zeeshan Mahmud

hello

Srivatsan

@ZeeshanMahmud hi

Zeeshan Mahmud

I am scared.

Rajesh D

07:43

@Sri difference between method 1. and method 3.

Srivatsan

@ZeeshanMahmud ??

t.b.

Hi all.

Rajesh D

hi t.b.

nice to see you

hi @Zeeshan

Zeeshan Mahmud

Well, I do not know the etiquette in chat. In the main forum I am overwhelmed by the formal tone. Other day I sweated when I got downvotes. Is chat relatively an informal setting? :)

Srivatsan

@tb tb, Just in time. I am copying your style from the Holder-Minkowski answer :-)

t.b.

07:46

@ZeeshanMahmud Don't swear too much. But all nonsense is welcome :)

@Srivatsan where?

Srivatsan

But I need vertical equals sign where you had \Updownarrow.

@tb editing an old answer. I am just a bored kid now =)

Zeeshan Mahmud

@tb I am easy with the swearing. My vice is casanova character of mine.

t.b.

@Srivatsan does \parallel approximately do what you want?

$\parallel$

Srivatsan

@tb Nah, it doesn't look too good for what I have. [Your answer looks very nice, btw.] I'll just drop it.

\parallel and \Vert are too long.

t.b.

@Srivatsan add in a space? $|\,|$

Zeeshan Mahmud

07:50

Hi Rajesh, pardon my bluntness but are you from India? :)

Rajesh D

@t.b. : just in case you are free please see this conversation here

yepp

Zeeshan you are too formal i guess

Zeeshan Mahmud

By chance a cricket fan?

Rajesh D

ofcourse i am a big no huge fan

Srivatsan

@tb Better. I will show it to you anyway. Give me a minute.

Rajesh D

@Zee are you also from India or if not Pakistan ?

Zeeshan Mahmud

07:52

It's funny I draw mathematical inspiration from Sehwag 219. He's a beast.

t.b.

@RajeshD I don't see what cardinality's got to do with it. You are choosing points wrt a distribution

Zeeshan Mahmud

@RajeshD Bangaldesh

Rajesh D

ok cool

you have done well in recent WC

@Zee

t.b.

World = commonwealth? Or are there other countries playing cricket? That sport is way beyond me. I tried for a week to figure out the rules watching people play on Parker's Piece in Cambridge.

Zeeshan Mahmud

@RajeshD Right now BD is getting killed by Pakistan. Re:Sehwag it's akin to climbing everest and sometimes problem solving is akin to mountaineering...

Srivatsan

07:54

@tb Look at the answer. math.stackexchange.com/a/64864/13425 I will change it back in some time, I think.

Rajesh D

@t.b. : So what is involved in choosing points from an arc of circumference and selecting the mid point from inside a segment in choosing a chord....i mean the difference between method 1 and method three in the solutions to B's paradox in its wiki page

sorry for the lengthy post

Srivatsan

tb: It's kind of overkill for what I need there anyway.

Rajesh D

@t.b. : Its called a Gentlemen's game !

Srivatsan

Sh... you might want to say Gentlepeople's game.

Zeeshan Mahmud

Hardy was a huge fan of the sport btw...

Rajesh D

07:58

why.........r u tryng to include women's cricket

Zeeshan Mahmud

Being the nerd i am, i wonder if research has been done in predicting sports score? :) (i know they did in soccer world cup)

Srivatsan

@RajeshD Well, ignore my comments. It's late here, so I am just rambling. =)

Rajesh D

@Sri how do you remove comments...teach me

Transcript for

$Mathematics$ Mathematics