Given a wire of fixed length we can bend it into a circle

Likewise.....what is the shape of a 2-d sheet i need to make a 3d sphere ?

@J.M. : @Asaf: you people there ?

The problem is that the plane has zero Gaussian curvature, and the sphere has positive Gaussian curvature...

Have you ever tried wrapping a ball as a gift?

a ball as a gift , how is it possible ....i am not able to get it

You should read this...

You can't make a perfect sphere but you can get arbitrarily close to it with polyhedrons

Okay, apparently giving wrapped gifts to other people is not a custom in your native land... let me think of another way of putting it.

Bon-Bons!

got it, wrapping a plane sheet of paper around a ball (gift)

So what is the analogy of bending a wire into a circle in 2D ?

What do you mean?

What does it mean to bend a wire into a circle?

i do not know the exact math formulation

Something like a piecewise differentiable length preserving map?

I guess

is it homeomorphic ?

but then every two curves of the same length are equivalent aren't they

yes

so in 3D it would be area-preserving

ok

and I guess that implies some other quantities are conserved

what about 2d ?

That was piecewise differentiable length preserving map

i think its 2d

i mean wire to circle is 1-d

okay

I was using 3D and 2D where you used 2D and 1D

got it

let me stick to 1d and 2d

so how can we get a spherical surface ?

what do you mean "get"?

as how i got circle from a piece of straight wire

glue its ends

starting from what?

yes

are you talking about topology?

what is the problem

i donnow whats invoved in it

but i need it

are you kidding or you're talking about the rigor math?

non-rigorous math

i am not kidding

Rajesh,

Starting from what?

i donnow what i should i start with

thats the question

Start with a sphere

Then you don't have to do anything to get a sphere

@RajeshD I saw your first message

i want to start with plane sheet of paper with any shape

i want it planar

so, any plane sheet of paper is homeomorphic to a plane itself

Look, you can't wrap paper round a sphere without creasing. Did you read the thread I linked to?

How do we know the area preserving maps also preserve Gaussian curvature?

and the plain is a sphere without a north pole

yes

@RajeshD imagine that you've cutted off the north pole of the sphere - then you can unbend it in a plain sheet, so you can start with a plain sheet and bend it to a sphere without one point

do you mean getting a hemisphere from a plane disc

yes, you can

just by projection

Without that, I don't see how we can apply the theorem

but you can also get almost the whole sphere without any small piece

Gortaur, that doesn't take into account preservation of area though

which is an additional restriction on this map

@JM Oh, you did? Hope you didn't confuse me with this guy...

Oh not that, t.b. The picture I saw had you near a blackboard... :)

@JM Ah, Asaf, the king of the white hat trolls :)

Oh, very good, then it's probably me :)

I'm pretty sure. It was one of your friends who posted; I forgot which one.

Hmpf.

Paul Balmer has pictures of his former students on his home page

He was my co-advisor.

Coadvisor is the one that you give the wrong advice to?

Yes, exactly. :)

These co-jokes never get old...

I saw a user on this site whose profile says he is from ETH...

Christian?

I don't recall.

Wait...

Why are you holding a glass of champagne in that photo??

Christian Blatter is a professor emeritus. My very first lecture I had at university was his geometry. Then there's Matt, a 3rd year student.

Why not?

That is a good point. I'll start bringing beer to my classes.

It was one of my many "last talks" at ETH.

Oh, and then there's Sam, a third or fourth year student.

"many last talks" - :D

@t.b. Oh, Christian Blatter was your professor at one point? :)

Yes, he was. I had a geometry course with him, then one on wavelets and one on convex sets.

He gave very nice and well-organized lectures.

Apparently "plagiarism" isn't something on his vocabulary......

@JM: I've commented there just now

I've also edited your answer here if you don't mind: math.stackexchange.com/questions

instead of "borrow" should it say "lend"

if A lends X to B then B borrows X from A

Yes indeed.

I wonder how many days before Henning gets his Epic.

@QED: thanks, I've fixed it

the Eye, he-he

@AsafKaragila what's epic?

"borrow" and "lend" are asymmetric operators.

@AsafKaragila Wanna take bets?

Wanna run it against your 20k and my Generalist? :-)

(I'm also considering starting a wager for when Arturo reaches 100k...)

At most three months :D

@Gortaur: thanks for that. :)

@Gortaur This.

Brian M. Scott seems to be hitting it strong on the reputation too.

IMO this plagiarist guy is a perfect example of how broken the rep system is. Contribute some basic number theory, some Hints and you'll eventually end up having 10k.

(reminds me of another user that isn't exactly reluctant to re-post stuff...)

This is after all a site awash in number theory questions... :D

Reminds me a user that got suspended for a while for plagiarism...

@Asaf: wow, that was way long ago...

(it was before your time, t.b.)

Yeah, a long long time ago. In a Samsung Galaxy SII far far away...

@JM: I don't think so, or it happened twice: there was an episode while you were away. He had himself nuked out of the system, but then re-joined. There are traces of that on meta.

@tb second it

@JM do you know what this guy wants from me? btw, getting downvote there seems weird math.stackexchange.com/questions/76661/…

Ah, yes; that second wave was around the time of my hiatus, IIRC.

@Gortaur: I replied to him. I wonder if he objects to \log\,2 as the answer to a question...

ah, you've already wrote him almost the same comment )

crap, I really wonder if we can have obligatory 15-character-comments if you downvote

Yes, that would be nice... but I upvoted already so I cannot compensate for that.

when I do it, I always put a comment what didn't I like and how it may be improved, otherwise those brave anonymous guys just downvote everything without any justification

Ditto.

@JM that was not the reason for what I've started complaining

I just pissed-off

I wonder what Brian means in his comment here

Interesting. I would not want to pry, though.

(He's a member there, yes?)

No, I don't think so. I haven't seen him there, yet.

@AsafKaragila people are all different

@Gortaur People are different, but they all die the same.

when we bleed we bleed the same

That's just not true.

that's Muse

So, let me get this straight: this guy contributed only "This example should illustrate the "LUX" method:" and the switching of two paragraphs?

don't touch'em

@tb which one?

The one J. M. just linked to.

@tb At the very least, it doesn't look like an entire copy-pasta; there are misspellings that weren't in the original.

lol!

That makes no difference to me. At all. It makes it worse, I think.

Despicable.

I know; I'm just musing that he actually typed the blasted thing...

WHAT?!

Maybe he's really new at this...

He's just not reading right.

@Gortaur: your answer would easily have fit into a comment box :)

not with the words in italic )

@Gortaur: Also adding "If you downvote please tell me why" is annoying.

downvoting without telling the reason is also annoying

Add a comment to your answer with that message.

but maybe you're right

Why does that line remind me of Birch-Swinnerton-Dyer?

good idea, thanks

Which line?

The one Asaf recommended to move to the comment box

... and he did it again.

I haven't read the original BSD paper, so I guess that's why I'm missing something...

who?

@Gortaur: sorry, you can't see it...

@t.b. it's like a zombie that won't go away...

@JM I was thinking of a guy who prefers to put spacing before punctuation.

Why would someone do that? It looks weird .

it does indeed .

@t.b. Ah! How daft of me... :D I get you now.

If even Arturo gives up on you, something is fundamentally wrong...

I graduate in two weeks and I have still plenty to do. Ahhh!

@JM Where? :D

@Jonas: so hanging out here isn't exactly the thing you should do right now, is it?

@Asaf: I won't spoil you; just look at Arturo's actvity page...

Yes, but this is excellent to procrastinate with.

It may help to browse the featured questions.

This way I feel like doing something useful.

Right.

@JonasTeuwen Wait, you don't know that the weeks before graduation will be one of the busiest parts of your life! :D

Well, it is just a MSc graduation for the moment.

@JM: For me, it was the week after. Still hung over, I guess :D

I wasn't counting the wild partying after you know...

"Wait, what?! That one has a deadline too?!! AAAAAAARRRRGGGGHHHH!!!!1!"

Oh, right, I have to arrange that too.

Hmmm. Interesting!

Doug's -17 question does not appear on the Featured page.

That one has a bounty attached?!

@Jonas: no need of doing that. These things tend to arrange themselves...

Even better, then I can procrastinate even more...

@JM Which else?

Seems like you have the proper attitude for doing a Ph.D. :D

*facepalm*

Well, I do work on the projects, but if they are practically done I seem to lose interest. I need to fix that.

Sadly you cannot delegate everything...

Actually they delegate the things to me...

@JonasTeuwen when and where is your defence?

@Gortaur 17 of November 14h at EWI.

EWI is large ) which room?

I don't know yet.

But usually, in the hall there is a screen that will say which room it is.

I won't come ( there is a guest professor giving talk that date, at 14h in our group

Oh, too bad.

@Gortaur: Go to his defense and throw rotten tomatoes at him.

No! Not again!

@JonasTeuwen you're skipping our lunches, what did you expect? ;D

Asaf, what are you drinking right now?

@AsafKaragila I better would come to yours

@JM my blood ((

@JM Actually I'm slightly dehydrated at the moment, not drinking at all.

@Gortaur Yeah, but you'd have to learn Hebrew to understand me...

@AsafKaragila should I understand you to throw rotten tomatoes? really? )))))

@Gortaur In my case? You would have no choice. I'd force you to sit and ask questions.

@AsafKaragila your force is not strong enough, young padawan

@Gortaur Usually I show up after 12h30!

facepalm Not enough set theory you have read.

But when I will be there earlier, I will tell you.

Too much set theory I have read.

@AsafKaragila and by the way - usually I force myself not to ask questions, because once on the first year of my BSc I asked the question at defence of one PhD which almost broke up his defence. My supervisor asked me kindly be more careful

Not enough care, Gortaur has. ;)

Aw man, those dissertation-breaking questions... :)

@Gortaur I honestly doubt you could tackle me on axiom of choice issues in my own thesis. I can let you try, though.

I could come and ask you something about Hardy spaces.

@AsafKaragila you're brave and young. nice. I wish you never change this position

Which I will vaguely relate to your stuff.

So Asaf, your worst nightmare would be that you were just studying the null set all along?

though you will lost youth soon

@JM Not really... the existence of the null set is enough to ensure the rest of the sets.

My worst nightmare is that ZFC will be proved inconsistent before I have tenure. I hope they prove its inconsistency a day after my tenure is in order, that way I could really do nothing at all.

Okay guys, I guess I'll go out and enjoy a little bit of the beautiful weather we have around here. See you!

@Gortaur One sort of youth I will never lose, the other I had lost years ago.

@tb: No rain? Impressive! :-) Enjoy.

See you t.b.!

@tb see you )

@AsafKaragila don't follow stereotypes

See you!

@tb don't forget to take an umbrella

@AsafKaragila Well, it's the season in which I think: well that'll be the last day this year that the sun shows up!

Bye!

Don't jinx it Gortaur!

@JM is it about my huge Eye?

nono, it was when you mentioned the umbrella...

it's a Murphy thing.

@JM I did understand you. It was a joke. Laugh )

For your eye I recommend artificial tears and some rest. ;)

@JM I cannot close it, you know (

Fish rest, and they can't close their eyes...

Have you just compared me

and fish?

@Gortaur I have a question

I suppose so. :)

@JM ok )

@RamanaVenkata go on, hi

@JM If I meet the guy who will use Euler phi function for this: math.stackexchange.com/questions/76671/… I would say Monsieur knows a lot about distortions

@RamanaVenkata: are you still here?

I came across this statement"If A is a subspace of X and B is a subspace of Y then the product topology of A x B is the same as the topology A x B inherits as a subspace of X x Y" What is meaning of this?? And It is also said that It is not possible for order topologies. Can you explain these statements with an example if possible??

Yeah a small network problem

Ramana, draw the commutative diagram

Meaning is that you can put a topology on a set in different ways

for example: A x B is a subset of X x Y

so we can put a subspace topology there

but also A has its subspace topology from X, B has its own from Y

so their product A x B can have a product topology based on subset topologies of A and B

the question is if these two ways bring the same topology on A x B

@Jack: Let me know when you're here. I have a couple of questions to ask :-)

@QED i dont what are commutative diagrams yet

They are a tool that helps organize and understand statements of the type you were asking about

@Matt: good afternoon

@Gortaur Okay What about order topologies??

@Gortaur, still 10am on the east coast, afternoons in 2 hours :)

@RamanaVenkata yeah, what about them? )

Compare the first two results of this Google search...

@RamanaVenkata what is the precise statement?

@JM found smth again?

@JM: google.nl/…

Let X be an ordered set in the order topology. and Y be a subset of X. The order relation on X when resticted to Y. makes Y into an ordered set. How ever the resulting order topology on Y need not be the same as the topology that Y inherits as a subspace of X

Right. Anyway I've bumped the meta thread. Hopefully something happens.

@robjohn Hi Good morning

good morning.

@RamanaVenkata yes, indeed

@robjohn good morning, have you slept well?

@JM that's nice, this guy is quite annoying

@Gortaur Can you explain that statement??

@RamanaVenkata and again: you have two ways to put a topology on Y: order topology and subspace. they may differ in some cases

I napped for a few hours after getting back to the room, but I've been up for several hours. I disconnected so that I could take the phone to where I could hear it while showering.

@JM where have you done it? cannot find it

I just plugged the phone back into the computer.

@Gortaur See meta.

Who is annoying today?

@JM I may surprise you but I cannot see your question there

@Gortaur: not mine. I bumped up Pete's thread.

Hey rob. I linked to a certain Google search above.

@JM v_v7who is Pete?

sorry, I really cannot understand you and find the thread you're talking about

this

@JM: shouldn't there be references to these examples? At least T.. and Ryan are quite sceptic

Ouch. A lot of what everbody posts has come from some book, or some class they took. Certainly there are original answers to some problems, but if we are going to have to reference everything we say, this is going to get tedious.

@robjohn: have you ever copy-pasted smth like Wiki without just puting a reference on it?

nope

uc

if you type the answer from 1 or 2 books - that's ok - you put your effort on it, and if the answer is right it deserves some upvotes

I try to rewrite things in my own words at least. Ah, so someone has been copy-pasting straight from Wiki?

google.nl/…

when you've found smth on the web - you've already have this address in your browser, right? 5 sec are needed to copy-paste the address as well

I always write in my own words because I hope that it would be more undersatndable for OP: puting some examples e.g.

Is Gosper's first name Bill? at least that is new :-)

"smth" ugh

@robjohn that's from wiki ))

@QED what? does smth in my post annoy you? )

painful to read

sorry ))

I'm just kidding. Bill was prepended to the Wiki post he copied.

But everything after is direct plagiarism.

@robjohn you're convinced! )

the day was not useless

Unless he wrote that part of the Wikipedia article. :-)

I don't think it matters )

So if I use something from an old sci.math post of mine, do I need to attribute it?

If so, I may have plagiarised. :-(

ok, I guess there would be your name against that post

on sci.math

@robjohn with sci.math you mean the part of mathforum?

it's not plagarism

@QED which one?

if you wrote it

even if it was a year ago

it's just failure to cite

icic

@Gortaur no, I meant the usenet group.

but the other guy is definitely plagiarizing, he even pretended not to have copied the text from somewhere else

@QED you can use your up arrow on the keyboard to edit the previous message

nice!

@robjohn there is smth that you've written and smth that you haven't

like in life: when you quote widely someone else you usually quote his name as well

Any defense, other than "I wrote that part of the Wikipedia article" (and it is substantiated) is bad

@Gortaur I don't understand the question.

@robjohn it's not a question ^0_o^

anyway, I don't think you should quote yourself but I do think that you should quote web-sources from which you have copy-pasted

sorry, I have to go to talk to my SV

@JackSchmidt: hi ) Asaf has questions to you I beleive

If I say that "someone told me" (because I can't remember who), then I expect that that will be taken with a bit less certainty than if I say "Gortaur told me". However, at least I am saying that it is not my idea, and that I don't remember whose idea it was originally.

It's the thought that counts I would say.

@JM Indeed.

On the other hand, I think it's kosher to say "this was from something I posted on sci.math a few years back..."

However, intent is very hard to divine sometimes.

Oh, purple is the color of the day!

I think I have said that whenever quoting from an old post. I can't say for sure that I have each and everyone, which is why I said that I may have plagiarized.

@tb IP changed again?

Hmm, if it were me, I would make my best effort to find my old stuff. If I have forgotten and somebody chides me, I will definitely include the source right away instead of being coy.

I believe it to be very hard to attribute things that you just internalized a long time ago. It would be tedious to read in all answers "that's something I learned from Rudin's book, I think you can find it there but here's the argument." However, if you copy something more or less straight from a book then I suppose you should say that.

Doesn't cost you anything at all, and chances are that this pointer will be very helpful because the interested reader knows where to find more.

@tb Yes, but telling the story anew in your own words is not plagiarism to me.

@robjohn: I definitely agree with that. There's a difference in reproducing from memory and copying...

As long as you are not simply transcribing it.

I think we agree :)

yes

You're both certainly right. :)

@t.b. yep, I found another example. Sheesh.

someone somewhere must have written a robot or spider to search the web for copied material.

@JM This is plain shameless.

@JM: somebody's looking for you...

Wow, I'm an example now! :D

@Gortaur Howdy. I suspect I'll be away most of the day, but just @ ping me if you want me to read it.

Does @robjohn notify me even if said in a chat room to which I've never been?

or does it only work if I am in that room when said?

I don't think so...

Off to get breakfast with other Nightfallers (Nightfellows?) BBL

owls

@AsafKaragila Here!

going to try my rep recalc thing, hopefully I can get it back quickly

ok, removes the tools instantly i think

Aw...

@JM: well, that was quick...

OP already switched to Joel's...

Well, glad he did, why are people so eager to accept quickly?

"get it over with and move on"?

A lot of people are like that...

No patience and all that.

I added a comment to that end.

@JM you should continue: when I was younger...

e.g. I've already written here when I was 1 month younger, @tb hasn't changed his gravatar so often

No, I'll just finish with "Get off my lawn, you damn kids!"

@JM who was it? )) Rob, I guess

No, it's an old Slashdot meme... :)

You reminisce about "the good old days" and then tell the kids to get off your lawn.

icic

hrmph, I should have checked the question list before recalcing. only one i can answer and Nicky H already did.

I wish we play chess this evening with my supervisor but he had to leave

maybe I'll start an even more exclusive 9.9k club

What is 9.9k?

9900 what?

oh

ok

seems like you hiccup )

@JackSchmidt in which area are you good?

aha, group theory. Let me realize which questions do I have there )

yay

damn, I don't have any good ones currently (

its ok. I should be writing and printing a worksheet anyways

damned Lee has perfectly answered all questions which appear in your head while reading his book. damned perfect book