It didn't work, Matt.

Yes, I noticed.

Well. The day passed and I had no reputation whatsoever... tsk tsk tsk.

I had really nice day for a change.

Me, too.

And I'm going to sleep now. I hope I don't dream of astronauts and space again, that was weird.

I fear Mondays are gonna look like that until summer is gonna come.

Don't ... you know what : )

Night folks.

I mean, I am not gonna have much computer time on Mondays from now on.

What with the seminar and all that.

Good night, Matt! Enjoy your free week!

Gute Nacht, Matt!

I will/am : )

And before I forget: thanks for today!

Sure!

Glad I could help.

What Asaf said. :)

:3795705 what was that with the determinant of the Jacobian again ?

Screw that smiley!! :-)

:)

Heya!

@AsafKaragila what is a good recipe to get 112 rep?

One Enlightened badge+3 answer downvotes.

But people delete their answers I downvote and I get my crappy rep back!

Find answers by deleted users! :-D

Oh, good idea!

Am I evil or what? :-)

Almost like Chuck

You're into Death lately, have you finally gone extreme metal?

Did anyone mention evil black norwegian satan music?

No, we mentioned death metal.

Ah

In particular Chuck Schuldiner of Death.

No, I haven't listened to that in a very long time. I've seen them like 13 years ago.

Awesome.

Awesome to the max.

That was fun

Death the band where the vocalist shoot himslef, and the band put him on the cover of their next album ?

No he died of cancer.

@AsafKaragila but I liked the performance of Testament even better.

Oh, sorry. I was thinking of Mayhem, silly me

That was Dead.

(The vocalist)

Oh yeah I always mix up those Chucks

@tb You know, one of the recent albums by Testament was designed by an Israeli guy named Eliran Cantor. He's the great-great-grandson of Georg. I know because I once met Eliran's father which told me that.

On 8 April 1991, Dead committed suicide in the house owned by the band. He was found by Euronymous with slit wrists and a shotgun wound to the head. Dead's suicide note notably read "Excuse all the blood, cheers." and included an apology for firing the weapon indoors. Instead of calling the police, Euronymous went to a nearby store and bought a disposable camera to photograph the corpse, after re-arranging some items.[9] One "

@AsafKaragila I only have The Gathering.

That band is great

Old school.

I only have "The Medalion" though, although it seriously kicks ass

As I said, I haven't listened to that stuff in a long time.

@N3buchadnezzar I meant this

@AsafKaragila Have you heard of Melechesh?

Yes.

Its good, never listened much to it though. I jsut remembered it is from the middle east.

@AsafKaragila Looks like it's this guy

Yeah.

What's awesome that in the "THE FORMATION OF DAMNATION" cover he used faces of Israeli metal sceners for the angels. In particular it was a birthday present for the guy whose face appears on one of the angels relatively close (I think the one holding a shield).

Well, I never really got the hang of this music. I have maybe a dozen of those albums, but it was more like an excursion towards the more extreme. Nowadays my taste has mellowed down a lot.

I think I'll just run an all nighter and start writing that paper on Whitehead's problem.

Sounds like a good plan :)

Yeah. No uni tomorrow anyway.

Which is good, since I have to teach on Tuesday morning.

Actually. I'm going to sleep. Too tired...

Then have a good night!

Thanks! :-)

So I'm not gonna post my AC question now... :)

(would have to think of one anyway)

What AC question?

Jerk! :-)

Good night, and sorry for committing this unforgivable sin of mixing up those Chucks yet again... Some neurons must have short-circuited there.

Oh, it's fine. I'm mixing between you and that other guy all the time... :-)

So... have a good night and show Whitehead hell tomorrow!

@tb Thanks. I hope to finish this in like three days... this way I can get uberwasted on Saturday (St. Patrick's!) and waste the next week on grading the resit (yes, we didn't finish grading yet! It's been like three weeks!!) and then hit the thesis with all my might.

@AsafKaragila is there anything enjoyable awaiting you till summer (except summer?)

@tb Well... there's always beer...

Anyway, don't want to keep you from your well-deserved sleep...

Alas, I'm actually doing some research lately.

Nothing deep and fancy, mainly doodling. It's still fun though.

@AsafKaragila yeah, my questions usually exclude the obvious... :) Good night!

Gute Nacht!

(I'm a bit on edge, I haven't slept since 1945...)

Oy...

Mr. Hilter, I think this is one of the better sketches of the Pythons.

@AsafKaragila Anyway, Layla Tov, and tell me about what you're doing when you have some spare time

@tb This is going to be some focal point, I have an idea what and how to do it. I'll have to see into the details as I go.

Now yes, sleep.

@AsafKaragila the https in the protocol causes problems. When I changed it to http it worked.

@DylanMoreland The one on google books is what I have. Confirmed it says $v \circ u \circ f = 0$. But then since it's a typo we can move on from that

I have the 1969 edition that has green on the cover

@anon Into Photoshop these days?

too lazy, I just use mspaint.

;-)

How do you do?

@KannappanSampath arent u in ur class?

Pretty good.

8 minutes to go for the class! @SivaramAmbikasaran

Can you be on the internet during class?

@KannappanSampath What class is it in 7 minutes?

Probability.

@anon Yes and no. Yes, I can be logged in. No, I cannot chat. :-)

cool. What are you currently doing in probability?

We are doing Jointly disrtibuted continuous random variables.

(Notions of convergence of sequences of Random variables.)

ok.

The classes being at 10 is it?

Pretty late

but good :)

@SivaramAmbikasaran Yes, at 10. And, I am there. :-)

Bye all. BBL.

Bye

hi everybody

hi folks

small crowd tonight

yo

what's the topic of convo tonight?

same as always: whatever we want it to be

not math? !

not necessarily math

I didn't type that last comment. what is it?

it says i can perform some action again in 1 second.

what in the world are you talking about?

i guess only i can see it

screencap it

That's not a comment, it's a message to you. Your connection to the chat boinked out temporarily so your comment of ": D" didn't go through. The 1 sec thing was probably so it could sync up again or whatever.

oh. ok. i thought something like that. :D

if you want to ask a geometry question, how do you make the figure?

me? mspaint or google images. :-) but there's tikz or geogebra or other things if you're interested.

(I don't think tikz works on the main site, you just have to upload the generated pic.)

i used tikz for images to put into my thesis' proposal. that was a pain in the butt. and i'm not very good with it

i'll have to try geogebra one day.

exit

sup meanie

oops

do reputations on this site start with 1?

even if you have reps on other SE sites?

I think if you have enough rep on one SE and go to another you get a 101 start on the other, and a +100 boost to your global rep. There might be differences between normal SE sites and betas though.

hmm, I have 400+ rep on SO

and I only have 1 rep here

i wonder if it's a bug

wow can't even ask a question on meta without 5 rep >.>

What's the question?

oh just about my possibly "bugged" reputation

I'm supposed to have 101 but I have 1 rep

anyway not too much of a big deal since i just want to make a comment about cross posting on some questions here

and it's a drag not having enough reputation to add a comment to a question

@Ken It appears to be a system lag issue.

ic

If you post your comment as an answer, people (e.g. me) will flag it for mod attention and then a mod will swoop down from on high and convert it to a comment free of charge. You don't want to do that regularly though :)

@Ken Try going to math.stackexchange/reputation and click rep recalc at the bottom.

meh not working

oh well

:-(

well i "answered" the question and flagged it

not very elegant but

it will have to do i guess[

Yes, back from class.

I feel like a naughty kid again.

@anon did you post that Q? :D

What question? It's a category.

oh. i thought you were referring to the first Q there

No, I saw the schlicking question advertised on the MSE sidebar, believe or not, and rofl'd.

Finally, he wrote a reply. Thank god!

Lunch time and I am buzzing off!

@KenLi I think you have to have rep on TWO other sites, in order to get the 101 free rep points.

@David, have you seen how many sites Ken is on?

Mother of Christina!

Maybe there's an upper limit on how many times you can get the +101.

I don't think so. The reason they have the bonus thing is so that non-newbies can have basic privileges.

We should run an experiment. One of us could just keep on joining new sites, until we either stop getting the +101, or run out of sites.

I am not in. :-)

I am finding Atiyah a comfortable journey. I have not met his crude face may be.

@DavidWallace OK. I opened an economics account so I could ask a question that I've wondered about.

...that's enough for today.

Does anyone how to share documents which you have on Google docs?

make it public and get the link?

check the box next to the documents you want to share on the gdocs main page. then click the "Share" button above the list. after that you have you open a doc you want to share and copy the url and give it out. I haven't used gdocs in few years though...

I see. What I want to is post some links for the CA room.

(I have fleshed out the proofs of various propositions in AM Chap-1)

Are you writing a textbook?

lol

sure. why not? I mean, if you did every proof in the first chapter! :D

@Jeff No. I am just adding substantial material to Atiyah. It is dense for a beginner like me that I have to think so much and end up seeing more general things that could be a Lemma, from which seeing the proof becomes an easy task.

@anon Tsk.Tsk.Tsk.

what's "Atiyah"

It is the pet name of a book called " Introduction to Commutative Algebra" written by Atiyah and MacDonald.

oh. well, it sounds like you are less of a beginner than i am

@DavidWallace There's a button in your profile (at least on the Economics site) labeled "Save and Copy Profile to All Stack Exchange Accounts"

I wasn't actually serious when I suggested the experiment.

@DavidWallace i figured as much :D. besides, the button just copies your profile to the other sites you've already joined (it synchronizes them).

What could cause them to become unsynchronised?

One SE registers a change without telling the other SE's?

Actually, I have seen that. Somebody changed his name, and for a while, he had different names on different sites.

yes @anon

My question was rhetorical; I already knew the answer was "yes."

You can have different names and profile contents on different SE sites under one single UserId

ok

was this room dead for a while ?

you can see the timestamps

from thats where i got this doubt

for an hour or so

people are sometimes too arrogant

Oh my ! What exactly is meant by 'last seen' on profile ?

@anon

@anon first impression I had is that it is a passport page :)

@tb: good morning

@tb Morning.

Morning, Ilya

Morning all

@Jonas: what?

@Ilya Hi! 8-). I was just a 3mE.

With kopfschmerz.

oh no what?

Teaching with kopfschmerz is quite annoying.

kopf-what?

Is it the last time someone has visited this profile ? is it what it means

@tb: filling in data for the Chinese visa, I have forgotten to use CAPITAL letters

No, the last time he logged on.

@RajeshD It's more or less the last time the person visited the site.

Oh my...I did not know such a thing existed

@tb although it sounds like something detectives would like to know

@Jonas: kopf-what?

yes

@Ilya schmerz = ache

@Ilya A headache. But I use the German word because when you say it out load it sounds really bad.

SE allows users to spy on each other Darn !

@JonasTeuwen indeed, it does. What have you done at 3mE? are you giving classes in our building?

@JonasTeuwen I knew that! But when I read your comment, I wondered whether Kopfschmerz was the author of the textbook that you had to use.

@Ilya: what example were you talking about yesterday?

@tb: Urysohn function

Oh, yeah, but it comes down to the same as the one Martin was giving (for characteristic functions of sets) but I was rather answering Jonas's query about proving Tietze in metric spaces without having to resort to the usual onion shell method. (and debunking Kaplansky's claim, of course :))

anyway, I liked it. Hope that your curiosity about my yesterday's comment didn't disturb your sleep :)

not at all :)

@jonas: I may have analgetic pills I usually use for a headache - would you like one?

No, thank you. :-). I feel okay.

A colleague of mine asked a question about piecewise-affine bijections on MSE; there are 5 upvotes but no hints at all. We were talking about that problem with her (about bijections, not about upvotes) and I don't know how to help. Maybe some of you have an idea?

I also didn't dare to edit the OP since she would realize that it's me who edited and I would need to explain here, why I've deleted exclamation marks for example :)

@Ilya what else would you like to edit?

@tb: :) typing it now

make the definition of $f$ in $$ $$and add the link for the paper

There are people who suggest edits removing thank yous and stuff as only modification. This is one of those very annoying things spilling over from SO. There's nothing wrong with being polite!

@David: yeah, maybe - personally I find them totally useless

Well, there rarely is any need for doubling or tripling up other punctuation marks than periods :)

@tb I am not saying about thank yous, regards (as TheBridge always does) etc. :)

@tb are you sure?!! :D

@Ilya I am!!!

It has been said that the use of multiple exclamation marks is the sign of a deranged mind. I think whoever said this just meant "person who thinks differently from me".

@DavidWallace maybe. anyway, any thoughts about the topic?

No, far too hard for me, sorry. I barely understand the question.

What difference does the superscript T make in the bracketed expression? Isn't it the same question if you omit this?

@Ilya better?

Sorry, I understand better now. Don't anyone bother responding to my last remark. It just needed a few minutes to sink into my old, tired brain. tb's edit helped.

I need coffee. I'll go drink plenty of espresso in the city center.

@JonasTeuwen sounds like a good plan. Enjoy!

@JonasTeuwen have fun :)

I'm always full of good plans... Thanks 8-).

@tb: much better, thanks

I'm slightly puzzled by the double index of $\beta$ though...

@Ilya btw. look at the description of the revision, I couldn't resist :p

hi

@tb what do you mean? everything, or just an exclamation?

@Ilya I needed to tell her that you were behind this, especially the exclamation mark...

@BenjaminLim hi. Have you figured out that exactness thingie?

No

the whole day I was doing field theory

@tb and how did you tell it??! :)

@Ilya Kagzila

@BenjaminLim omg, sounds like Godzilla

@Ilya like this

ah, the descritpion - I never read it :) I think, she also won't read it

hahaha, you and theo carry on I'll try to work out the exactness thing since Dylan has confirmed it is a typo

@BenjaminLim So. Repeat what you need to show...

So let me type up the sequences again: We want to show that assuming $0 \longrightarrow \operatorname{Hom}(M'',N) \xrightarrow{\bar{v}} \operatorname{Hom}(M,N) \xrightarrow{\bar{u}} \operatorname{Hom}(M', N)$ is exact

then $M'\xrightarrow{u} M \xrightarrow{v} M''\rightarrow 0$ is exact

we already established that $f \circ v \circ u = 0$

@BenjaminLim no, we've shown $v$ to be surjective (remember the image trick)

Oh crap my memory is failing me now

No, $u$ isn't injective (there's no zero on the left!)

Crap we want to show that $vu = 0$?

Ok. So to show exactness of that sequence we already have exactness at $M''$ because $v$ is surjective

Yes, that's part of what we want to show.

@BenjaminLim right.

so now we only need exactness at $M$ which is where we want $vu = 0$

sorry man that isaacs stuff really drained me....

So, choose a suitable $N$

well what if we take $N = M''$

$f$ the identity map

then what?

then we have that $v \circ u =0$

wait

you see

i don' think exactness is equivalent to saying that $vu = 0$

I hope you don't think that :)

well I think exactness implies that

but not the other way round

That's true, but it still is part of what you need to show. What does $vu = 0$ tell you about kernel and image?

whatever in the image is in the kernel

so, $\ker{v} \supset \operatorname{im}{u}$.

yes

Now I am thinking second isomorphism theorem

$M \supset \ker v \supset \operatorname{im} u$

Well, you haven't really used exactness of the Hom sequence so far...

We already used that $\bar{u}\bar{v} = 0$

yeah, but that's only part of the information...

and we have also used up that $\bar{v}$ was injective

still only part of the information :)

what else is there?

two degrees of freedom used up (as the physicists would say)

So far, you listed:

1. $\ker{\bar{v}} = 0$

2. something equivalent to $\operatorname{im}{\bar{v}} \subset \ker{\bar{u}}$.

2. $\bar{u}\bar{v} = 0$

There's a third thing you know.

I don't know....

(and recall that you're still free to choose $N$ in addition)

Well for one thing you know also that $\operatorname{im}{\bar{v}} \supset \ker{\bar{u}}$ for all $N$.

That you haven't used so far.

I thought that was already used up in $\bar{u}\bar{v} = 0$

Nope, that was what I called 2.

(and it is equivalent to your 2.)

Did we not use it to deduce $vu = 0$?

Look again at the inclusions!

oh right.

@Ilya: I'm confused about the bijections question. How is that function vector-valued?

Also, why is $\beta$ doubly indexed if it's a vector?

@anon I suspected that $f$ should rather be $f_i$ but I didn't want to edit that.

@t.b. If $i$ is free then why does it appear under $\min$?

Right, that doesn't make sense either...

scratches head

@tb Ok so let's do the image trick again

Take $N = M/\operatorname{Im} u$

Then let $\pi$ be the canonical projection of $M$ onto the quotient

Now recall $u : M' \rightarrow M$

So that $\pi \circ u = 0$

or $\bar{u}(\pi) = 0$.

Where's a set theorist when you need one? Re: the current suggested edit.

@anon: I was thinking the exact same thing :)

This means that $\pi \in \ker \bar{u} \implies \pi \in \operatorname{im} \bar{v}$

So this means that $\pi$ factorises into $\pi = f \circ v$ where $v : M \rightarrow M''$ and $f : M'' \rightarrow N$

and what does this mean?

wait