Mathematics - 2012-08-25 (page 2 of 4)

user19161

13:12

@skull I see you are white.

BenjaLim

@JonasTeuwen My first answer on lie groups!

3

Q: how to show $SU(2)/\mathbb{Z}_2\cong SO(3)$

Could any one give me hint for this one? how to show $SU(2)/\mathbb{Z}_2\cong SO(3)$, well, Is it the same: there is a 2-fold covering map from $SU(2)$ to $SO(3)$? what is that map will be?

Ragib Zaman

@BenjaLim maths.usyd.edu.au/u/SUMS/res2012.pdf $$\huge :) $$

BenjaLim

@RagibZaman GOOD ON YA

Ragib Zaman

lol ty

BenjaLim

@RagibZaman Good onya

@RagibZaman Next time I see you we can go for tooheys extra dry

Ragib Zaman

13:18

@BenjaLim I've never had occasion to tell you but I don't drink lol.

BenjaLim

@RagibZaman wtf man

By the way anthony henderson will be in anu for the rest of the semester

Ragib Zaman

Yea i know.

Otherwise he would be teaching my modules/grp reps class

Which I would have liked.

BenjaLim

how is modules

Ragib Zaman

Its been kind of boring-ish so far IMO

We've been focusing on classification

BenjaLim

Algebraic topology is fucking hard man

Ragib Zaman

13:20

I want to see how its related to algebraic number theory.

BenjaLim

Like if you've noticed I've been asking so many questions on it

Ragib Zaman

Yea

Are many of your friends doing it?

It's better to do the courses you find hard with some friends to help each other along.

BenjaLim

well about 5 people

@RagibZaman I'm practically homotoping everyday

@RagibZaman classification of reps?

Ragib Zaman

No we're still in the modules half of the course

classification of modules over PIDS

PIDs*

BenjaLim

ah

that is a nice result ragib!

you must have learned the structure theorem!!!

Ragib Zaman

13:26

yea its pretty nice

But I'm yet to see much usefulness of all this theory other than Jordan canonical forms and a fancier way of seeing how to classify finite abelian groups.

In my rings/fields/galois course the lecturer weaved in lots of material about quadratic number fields which made it more interesting to me. I keep hearing about how you need modules for ANT so I want to see at least a bit of it.

BenjaLim

@RagibZaman No classification of modules over a PID = no tackling Neukirch

@RagibZaman Let me give you one example of this happening in ANT

Typically suppose you look at $\Bbb{Q}(\zeta_p)$

The integral closure of $\Bbb{Z}$ in $\Bbb{Q}(\zeta_p)$ is the finitely generated module $\Bbb{Z}[\zeta_p]$ over the PID $\Bbb{Z}$.

Gustavo Bandeira

In this question he says: "How to solve for $x$" Why did he said that? There's only one variable, isn't it obvious that one should solve for x?

Henning Makholm

13:42

@GustavoBandeira Dude, it's Rajesh K Singh. You could spend all your awake hours wondering what it is he means by his posts.

Gustavo Bandeira

@HenningMakholm HaHA

user19161

@GustavoBandeira Do you understand the answer I wrote?

Gustavo Bandeira

@JasperLoy Yes.

What he meant with "very large values of Pi?

user19161

@GustavoBandeira In solving equations, one way is to go bidirectional every step: a implies b and b implies a. a implies b means that if there is a solution to a it will be a solution to b, and b implies a the other way, so that anything satisfying the last in a chain of reasoning actually fits into the original equation.

Henning Makholm

@GustavoBandeira That's a joke.

Gustavo Bandeira

13:46

@HenningMakholm Ok, I was thinking: "Isn't Pi a constant?!"

@JasperLoy Can you point me an example?

Henning Makholm

@GustavoBandeira It is. The joke is only slightly subtler than the usual for large values of 2 formulation. (And no, neither one is a thigh-slapper).

t.b.

14:02

@JonasTeuwen The map $\mu \mapsto (1/\mu(1), \mu/\mu(1))$ is a homeomorphism $M_+(X) \smallsetminus \{0\} \to (0,\infty) \times P(X)$, where $P(X)$ is the compact space of probabilities. The product of two locally compact spaces is locally compact.

It follows that $M_+(X) \smallsetminus \{0\}$ is locally compact and it is metrizable if and only if $X$ is metrizable. (All this is assuming $X$ is compact).

user19161

@GustavoBandeira Hmm OK. If I try to solve $x-1=0$ for instance, I add one to both sides to obtain $x=1$, so that any $x$ satisfying the first also satisfies the second. However, how do we know that $x=1$ really satisfies the original equation? Well, that is because in $x=1$ we can subtract one from both sides of the equation to obtain the original. That is to say we have a statement of the form "P if and only Q".

user19161

And someone just made me upset in another chat room...

BenjaLim

@t.b. hey

Will you be around in 8 hours?

I have been answering several questions on AT/ lie theory now :D

user19161

@GustavoBandeira In practice, sometimes one can only go forwards but not backwards every step. One then has to substitute the last step manually into the original to really ensure it works.

t.b.

@BenjaLim Not sure. It's around midnight then, so maybe for a short while. (but I might go out, so...)

user19161

14:10

@BenjaLim Oh no, now he sounds like your servant. :-)

BenjaLim

@t.b. I have been trying to prove that if the exponential map from the lie algebra to a matrix lie group is surjective

then the kernel is indeed a linear space

I want to compute dimension

t.b.

?

BenjaLim

The trouble is, if $e^X = I$ I don't know that $e^{tX} = I$ for all $t$.

where $exp : \mathfrak{g} \to G$ is the exponential map

t.b.

Look at $\mathbb{R}$ and $S^1$...

anon

[exp(2pi i)=1, t=1/2 counterexample]

BenjaLim

14:12

@t.b. So it's not a linear space....

Hmmmm

I only know it's a subgroup then....

Ah crap............

I have been stuck on this damn problem

t.b.

Well, it's always a local diffeo, so the kernel cannot contain a non-trivial subspace.

BenjaLim

crap

Jayesh Badwaik

@JasperLoy This is what I think when you say you are good at smalltalk.
en.wikipedia.org/wiki/Smalltalk

BenjaLim

@t.b. I have been trying to show that if $G$ is an abelian connected matrix lie group then it is homeomorphic to $\Bbb{T}^n \times \Bbb{R}^m$

I am now freaking out I have to hand this in on monday....

Well I know that $\ker exp $ is a subgroup from the fact that $\mathfrak{g}$ is abelian

user19161

@JayeshBadwaik Oh no, I know zero programming.

t.b.

14:15

Well, you know the closed subgroups of $\mathbb{R}^n$, right?

BenjaLim

And I have been trying to see the whole day why $\mathfrak{g} / \ker \cong \Bbb{T}^n \times \Bbb{R}^n$

uh...........

@t.b. I don't think I do

t.b.

Then try to solve that problem first...

BenjaLim

Is it relevant?

@t.b. I don't see immediately how it helps....

t.b.

well, the kernel of the exponential map is a closed subgroup of $\mathfrak{g} \cong \mathbb{R}^n$, right?

BenjaLim

yes I agree. It is a subgroup because the lie algebra is abelian, and closed because it is the inverse image of 0.

Oh..............

Man this may be complicated....

@t.b. Lie groups absolutely rad man

t.b.

14:18

You want to prove that it is isomorphic to $\mathbb{Z}^k$ for some $0 \leq k \leq n$.

BenjaLim

where are the results on free abelian groups when you need them....

user19161

@gustavo And that day you asked me about making things like the trigonometric functions rigorous. Well, that will come later when you do analysis. No need to worry about these things. I think you are worrying about too many things too early.

Gustavo Bandeira

@JasperLoy Yep. I'm editing something, Ill read your example asap

BenjaLim

@t.b. How come you can see the problems so quickly?

user19161

@BenjaLim He has studied for so many years dude.

BenjaLim

14:24

@t.b. Night.

See you tomorrow morning

t.b.

Good night, see you then, maybe.

Gustavo Bandeira

I found one image I made months ago, the square root of three

user19161

@GustavoBandeira How does it represent that?

Jayesh Badwaik

@GustavoBandeira Dude, either use png or jpg.

Anyway, my question is the same as Jaspers.

Gustavo Bandeira

@JasperLoy The little program I made took the part after the point: 1.(73205), then it built a list with these numbers (7,3,2,0,5). Each number produce a color from 0 lighter color, to 9, darker color.

@JayeshBadwaik Dial up conection?

user19161

14:30

@GustavoBandeira WTF!!!

Gustavo Bandeira

@JasperLoy What?

user19161

@gustavo Was it you who flagged my "balls" message earlier on?

Gustavo Bandeira

@JasperLoy Balls message?

user19161

@GustavoBandeira Well, if you don't know what I am talking about, then never mind.

Jayesh Badwaik

@GustavoBandeira Currently yes.

user19161

14:32

Someone is flagging my messages and not telling me who or why.

Gustavo Bandeira

@JasperLoy I've seen now that there's a stared message about balls having a weird shape

Jayesh Badwaik

@GustavoBandeira As soon as there is a fibre to my home.......

Gustavo Bandeira

@JasperLoy It's not me, I consider you as a friend. I just hope you don't say me the samething Horton said.

user19161

@GustavoBandeira No, flagging does not mean bad intentions. It just means the person wants to flag this kind of thing.

user19161

But it has happened twice and I don't know who it is.

user19161

14:36

And others say similar things but they are not flagged.

user19161

So I am really trying to figure out what this dude is thinking.

Gustavo Bandeira

@Horton says this when girls say he's their boyfriend

@JasperLoy I blame @JayeshBadwaik... He has dial up connection...ppl with dial up connection is not so trustworthy....be careful....

user19161

@GustavoBandeira I have met many deceptive people in life, I know...

Gustavo Bandeira

I guess my english sentence sucks somehow... (That sentence on Horton).

user19161

It takes a few clicks to flag a message, so it is definitely not a finger error.

Gustavo Bandeira

14:42

@JasperLoy Do you receive a notification when you're flagged?

user19161

@GustavoBandeira I do because I have enough rep on SE to see it.

Jayesh Badwaik

@GustavoBandeira And your sentence on me sucks too.

Gustavo Bandeira

@JayeshBadwaik Umad?

Oh, I remember I've made a "song" with the sqrt of 3.

user19161

I am now seriously thinking someone has something against me, not being paranoid...

user19161

Twice in the room, with no explanation?

user19161

14:44

That dude can just tell me directly.

Gustavo Bandeira

@JasperLoy They have envy of you because you're sexy and you know it.

@JayeshBadwaik I'm just kidding.

user19161

I like to be open. I dislike people "stabbing me in the back".

Jayesh Badwaik

@GustavoBandeira Naah. I am not able to respond properly due to dropping network. I was typing up some kickass response and link dropped. I am mad, but at my broadband company, not you.

:-)

anon

what an interesting title

Gustavo Bandeira

@JayeshBadwaik If you had sent this kickass response, I would flag you as if there's no tomorrow!

=D

user19161

14:47

So whoever the flagger is, please tell me. I won't ask again, but this had made me change my impression of things here.

Gustavo Bandeira

@JasperLoy There's a book o Nihilism

user19161

@GustavoBandeira Oh I don't even know what that is.

anon

by process of elimination I would suspect Damir, but I don't want to jump to conclusions. I can't remember if these rooms allow unregistered users to view, also.

in any case, they might have left or not want to speak up

user19161

Anyone can view but I think it takes a user present in the room to flag.

user19161

But maybe I am wrong about that.

Gustavo Bandeira

14:51

Tell me one instrument?

Any instrument.

Orchestral instrument

user19161

Cello, my favourite.

Jayesh Badwaik

@GustavoBandeira If you had flagged me, there might not have been no tomm.

Gustavo Bandeira

@JayeshBadwaik Hahaha

anon

Texas Instruments

Jayesh Badwaik

@anon speaking of funny titles en.wikipedia.org/wiki/…

National Instruments

user19161

14:55

So what's with the instrument thing?

Gustavo Bandeira

@JasperLoy Wait a little and I'll show.

And I'll also comment on the Nihilism book.

user19161

This dude really made me upset in the other room just now, but I will get over it, not his fault I must add.

user19161

I did something on the site, he throwed me a meta post to show that I was going against community norms, not knowing that I have been on SE for over 9000 years.

Gustavo Bandeira

@JasperLoy Show this meta post?

user19161

I have read more meta posts and thought more than him about these meta posts probably.

user19161

14:57

@GustavoBandeira Nah, it's OK.

Clash

hey guys, could someone help me calculating the determinant of a matrix?

user19161

@Clash Just ask and see.

Clash

so, I have this 4x4 matrix and I want to calculate it's determinant, I have typed everything in wolfram alpha: http://www.wolframalpha.com/input/?i=det%5B%7B%7B1-X%2C0%2C0%2C1%7D%2C%7B0%2C-1-X%2C-1%2C0%7D%2C%7B-1%2C0%2C-X%2C-1%7D%2C%7B0%2C1%2C1%2C-X%7D%7D%5D
the determinant is x^4, which I can't see why. I tried using Laplace on the first line to get two 3x3 matrixes and the result is different, I must be doing something wrong: http://www.wolframalpha.com/input/?i=det%5B%7B%7B0%2C-1-X%2C-1%7D%2C%7B-1%2C0%2C-X%7D%2C%7B0%2C1%2C1%7D%7D%5D*%28-1%29 and http://www.wolframalpha.com/input/?i=det%5…

i have the same result of the determinant of the two 3x3 matrixes on my notepad

user19161

@Clash You know that when you use the first line to expand, you need to alternate the signs right?

user19161

Just checking.

Clash

15:10

yes

god damn, never mind... it's because I had this: -(1-x)(x^3+x^2+x) - x and I could have sworn that couldn't be x^4

is there any easier way looking at the first 4x4 matrix that it is in fact x^4?

user19161

@Clash It's correct, check again.

user19161

Just carefully expand everything.

Clash

thanks jasper!

user19161

@Clash None that I know of now. But there are special results for special kinds of matrices which you can apply.

user19161

Always look for the row or column with the most zeros.

user19161

15:15

Just a thought.

anon

the inner/outer columns are the same, respectively (of the original matrix, without the X). probably a few more thoughts on subspaces could show that all eigenvalues are zero

user19161

Anon comes to the rescue, but by then it is faster to just do a brute force than think about all these.

anon

yes, it is a relatively easy computation, all 4x4's considered.

user19161

I think exam questions only go up to 4 by 4 at most. :-)

Clash

I can see there are two linear dependent lines on the original matrix, but does this matter if it's without the x?

if there was a single linear dependent line on the matrix with x, then i could say the det is 0 and there is no eigenvalue, right?

anon

15:20

@Clash the determinant you have is clearly a characteristic polynomial, so it is x^4 if and only if all of the eigenvalues (over C I believe) of the underlying matrix are zero, so I tried reverse-engineering from there

sorry my connection keeps going out

Clash

yes, that is correct, i am searching for the characteristic polynomial

can i make assumptions based on the original matrix?

anon

what do you mean?

given the right knowledge and insight, you shouldn't need to make assumptions, but rather deductions :P

Clash

yeah like you said, the original matrix's columns are the same (inner and outer)

how can you from there say that it's eigenvalues are all 0?

yeah sorry, i ment deduction not assumption

anon

I don't really know of an easy way. This conceptual method is more taxing than just doing the straight-up computation.

Your only issue with it was making an unwarranted assumption instead of plowing forward with the computation.

Clash

is this considering I'm not a computer? what should be faster?

leo

15:26

hi!

anon

yes it is considering you are not a computer. you only had to do a linear combination of two 3x3 determinants, that isn't too difficult. if it is, you need to practice more... :)

Clash

oh ok, thanks! I thought someone could instantly notice based on the original matrix that all eigenvalues could only be 0 because there are two linear dependent lines

anon

not really, you can have the same situation with nonzero eigenvalues

leo

@anon some time ago I was thinking in something like "something about the Cantor set"

anon

cool

user19161

15:31

As cool as anon.

leo

hey @JasperLoy!

user19161

What's up?

leo

about to purchase

user19161

@leo I did a google search for the number and the browser thought it was an IP address!

user19161

No wonder it was so slow...

user19161

15:34

It slows down to infinity.

leo

@JasperLoy I see

user19161

But you might wanna check with the lecturer as well what he is using.

user19161

I find it weird that he gave you a biblio that had 9000 books on it.

leo

$9 for the Boothby in India

user19161

About 5 would do, not 9000.

user19161

15:36

Personally, I like Lee's books but the three belong together, so if you want one just go with Boothby.

leo

@JasperLoy He used to be like that

user19161

@leo I don't see the point of recommending such a long list, nuts.

user19161

@leo I also recommend you abebooks.com for cheap books.

leo

@JasperLoy He thikns we must learn as much as we can and that we must do many exercises (which is good). But for the course it follows its own notes

user19161

I don't know about all the laws about international editions, but if a seller sells it and I buy it and not photocopy the book I think it is OK.

user19161

15:39

@leo Good. Some lecturers use others' notes and go to class pretending they know what has been written.

leo

He don't have TeXed notes. We must go to his classes. I like the way he teach us. He is a cool guy

is "Pura vida" as we say here

user19161

OK, good. By the above, I mean that the lecturer uses another lecturer's notes and did not even go through them properly before going to class.

user19161

Not typed out is fine.

user19161

As long as the lecturer knows what he is talking.

user19161

Many don't know what they are doing.

user19161

15:42

They just go to class and sort of deceive the students.

leo

that's bad

but he knows what he is doing

user19161

Of course, I don't name these people. But I speak from first hand experience.

leo

I understand

Jonas Teuwen

16:15

@t.b. Thanks! A nice result. I should be able to come up with that, but my mind is not so sharp now :-).

robjohn

@JonasTeuwen Did I miss t.b. or are you talking to people who are not here again? :-)

anon

Both.

Jonas Teuwen

@robjohn Yes.

robjohn

@anon I hoped that my answer regarding the integral of the product of cosines was not too close to yours and actually added something to the discussion.

Jonas Teuwen

@robjohn I have seen you do mostly quite advanced technical thingies. Are you also well trained in functional analysis?

robjohn

16:23

@JonasTeuwen Ah, I was walking Lilly in the park then.

anon

@robjohn maybe, maybe not

what brought you to that old question?

robjohn

@anon It was on the front page. I guess Community put it there.

anon

oh, JM edited the other answer yesterday

robjohn

@anon Ah, that would explain it.

user19161

@robjohn If it is the latter, it would not be address to a teddy bear.

user19161

16:26

@JonasTeuwen Well, any analyst should be relatively well-trained in functional analysis.

robjohn

@JasperLoy well, I have seen Jonas @address J.M. when he was not here. I figured he might do the same to t.b.

@JonasTeuwen I didn't take any course specifically in functional analysis. I just picked up a few things in other classes.

Jonas Teuwen

@robjohn Oh, yes, but you should know some, but the LCS stuff.

@JasperLoy It is a huge field.

user19161

@JonasTeuwen Therefore, I added "relatively".

user19161

Come on, "functional analysis" can mean over 9000 things.

robjohn

@JonasTeuwen Longest Common Subsequence? not really.

Jayesh Badwaik

16:30

@JasperLoy Why are you so fond of 9000? Do you know about Ravana?

user19161

@JayeshBadwaik Well, it is a habit I picked up from the other chat room.

anon

because of Vegeta

google.com/search?q=over+9000

robjohn

user19161

I also like to say QED, so having given this warning, I will also use QED liberally here now. It means something like "case closed" in this case.

robjohn

@JasperLoy there is another chat room? ;-)

Jayesh Badwaik

16:33

Ohh, so its a present from Goku. Now, I remember that show.

Jonas Teuwen

@robjohn Locally convex space.

robjohn

@JonasTeuwen Oh, then perhaps a bit more :-)

Jonas Teuwen

Schwartz spaces! 8-).

user19161

@JonasTeuwen I thought you meant locally compact at first. Well I interpret LCH as locally compact Hausdorff and LCTVS and locally compact topological vector space.

Jonas Teuwen

My use is quite standard I suppose...

user19161

16:37

makes note

sos440

Hello, everyone!

leo

@sos440 hi

anon

@sos440 hey, I don't think I've seen you come to chat before

you have nice answers on MSE!

sos440

@anon Thanks! :)

user19161

@anon You have been stalking him I see...

anon

16:43

and a nice blog

robjohn

@HenningMakholm: "soak up the unearned rep gain myself"; way to fall on your sword ;-)

anon

@JasperLoy no, I just see sos's answers occasionally

robjohn

@sos440 I think I saw you here at least once before...

Yes, around this time

sos440

Yes

This is my second time to this chatroom

robjohn

@sos440 welcome back!

sos440

16:49

@robjohn Thanks for your welcome! :)

user19161

@sos440 Where there is a second time, there will be a third.

user19161

@sos440 Do you like kimchi? I know this other SE Korean guy who has kimchi every meal.

robjohn

@sos440 Sometimes we even talk about math here :-)

sos440

@JasperLoy I like it, but I does not eat it every time..

robjohn

not that you'd know it from this morning

user19161

16:50

@sos440 do, not does

sos440

@JasperLoy Excuse me for my poor English, my native language has grammar structure quite different from English, and I'm struggling with it...

Actually, it is the main reason why I have been reluctant to chat...

user19161

@robjohn I thought there are a few more here!

anon

like half the chatters at any given time are not native English speakers, or are at least bilingual

user19161

@sos440 Nah, you should come as often as you want.

sos440

@robjohn Yes, I'm also trying not to take care of it, too... :)

robjohn

16:53

@JasperLoy perhaps there are. I know that when someone asks whether it is better to say "x" than "y", I will suggest, but I rarely do otherwise.

@JasperLoy Don't get me wrong, there is often a need for grammar nazis :-)

Especially if people ask for help with idioms, etc

sos440

Wow... I just hope that those grammar nazis will help my English ability enhanced...

user19161

@sos440 You can consider joining ELU and/or its chat room.

user19161

That's my other hangout.

sos440

@JasperLoy I have never heard of ELU... Is it an abbreviation of English Language Users or something like that?

user19161

@sos440 Eng Lang and Usage.

robjohn

16:58

@sos440 English Language and Usage

sos440

@robjohn Oh, now I see...

user19161

The name of its chat room is Incomprehensible.

user19161

Indeed, all topics and languages in the world are discussed there!

sos440

@JasperLoy That sounds fantastic.

user19161

I think the ELU chat is a little bit more crazy than this one.

robjohn

17:00

@JasperLoy well, we are mathematicians, after all.

user19161

@robjohn But I think this room is also quite crazy sometimes, so very good!

Henning Makholm

@robjohn I am selfless like that. :-)

robjohn

@HenningMakholm It's good to know that there still are a few out there.

@HenningMakholm: I was going to comment that "even secretaries get paid" :-)

I might anyway

user19161

@robjohn I never understood why people want their answers CW.

user19161

If they want to comment, comment. If they want to answer, answer.

user19161

17:15

If someone left a comment that should be an answer, comment to him asking him to answer.

user19161

If he does not, then write up a detailed answer and post it normally as long as you understand it yourself.

robjohn

@JasperLoy That's my view, too.

user19161

I know people have reasons for doing that, but I have also thought about this for 9000 years.

Henning Makholm

@JasperLoy My motivation was that I wanted to avoid being be accused of farming rep by converting other people's comments into answers. But not if it comes at a cost to the OP.

user19161

@HenningMakholm Well, if you thought about it the same time as the commenter, then people should not accuse you. If they do, it just shows a lack of critical thinking skills.

user19161

17:18

Ultimately, we want this to be a great Q and A site where questions get officially answered.

user19161

Plagiarism is defined by the intention though it is judged (rightly or wrongly) by the effect.

Henning Makholm

But is there anything non-official about getting answered as CW -- except for the missing +2 to the OP?

user19161

Well, I don't know. I am not Jeff Atwood or Joel Spolsky, but I will say the following.

robjohn

@HenningMakholm I don't think so. It is totally a moral choice unless there have been a certain number of edits

Henning Makholm

And there are plenty of cases where I think after reading a comment that this ought to settle it. But I don't think whether the question deserves an answer should depend on whether the answer satisfies the commenter's personal standards for answerhood.

user19161

17:20

It does not matter too much what a meta post "agrees on" sometimes.

user19161

Community views change over time, and not everyone sees every meta post.

user19161

We see the meta post, we are aware of the issues involved, and we decide accordingly in a balanced way.

user19161

I think that is all that is required.

Jonas Teuwen

Well hello hello.

I need a kickass authorization library for python. Does it exist? I hope yes, otherwise I have to make it myself.

sos440

OMG, it's 2:25 am here...

More worse is that my head began to ache, and my face became red as if embarrassed. I think now it's just right time for bed...

Goodbye~

user19161

17:29

@sos440 Good night!

Henning Makholm

@JasperLoy I'm having some trouble seeing which implication these general observations have on the propriety (or not) of making answers CW. Where they meant to have one?

user19161

@HenningMakholm That was a response to your "is there anything non-official".

Henning Makholm

@JasperLoy But that was a response to your "a great Q and A site where questions get officially answered".

My impression was that you thought a non-CW answer counted more as "get officially answered" than a CW one did.

user19161

@HenningMakholm I would say that is extrapolation on my part. If an answer is editable by many many people, it will turn chaotic and not be truly solid perhaps.

user19161

Also, we do want people who post great Q and A to be awarded.

user19161

17:34

That is how the rep system works, so that privileges are meted out.

user19161

And so that people are encouraged to continue posting and contributing.

Henning Makholm

@JasperLoy Okay, I see what you're saying now. But now that everyone can propose edits, that difference between CW and non-CW is rather small. It's true there are more users with 100+ rep than with 2000+ rep, but there are close to no edits of other people's answers anyway. I don't think any of my CW answers have ever been edited by someone who is not me...

user19161

@HenningMakholm Also, another reason is aesthetics. Having "CW" pop up here and there instead of a name is just plain weird.

Henning Makholm

@JasperLoy Okay, that I can sympathize with :-)

Gustavo Bandeira

18:06

@JasperLoy I've completed it, it's a small music with notes generated with the square root of 3. The piano sequence is the square root of 3, the rest is a chaotic pseudo atonal structure.

Henning Makholm

18:33

There should be an option in bash, which one could enable in /root/.profile, saying that pathname expansion for a * surrounded with whitespace only happens in commands that are prefixed with pretty please. $\quad$ :-(

Jonas Teuwen

@HenningMakholm That is your punishment for using bash 8-(.

"De heer straft onmiddellijk" is a saying in Dutch.

Henning Makholm

@JonasTeuwen What would you suggest using instead?

Jonas Teuwen

zsh!

I have only recently started using it very intensively. Like a month a so... why bash ever?

Matt

Hello!

Jonas Teuwen

It is one of these things like "alcohol, where were you all my life?".

Hello.

Matt

18:41

whew I just wrote a one hour answer.

Henning Makholm

@JonasTeuwen Does that have such an option?

Matt

Oh yes, alcohol is the keyword.

Jonas Teuwen

@HenningMakholm It has plenty of hooks for pathname expansion! I don't know about this one, but I have like a "lazy expansion" setup now. If I make a typo it gives me alternatives 8-).

Matt

scampers off to the kitchen

Jonas Teuwen

@Matt Ah, but shouldn't your girlfriend do that?

Henning Makholm

18:42

@JonasTeuwen I don't want hooks that I can use to create my feature. I want the feature there, and preferably an hour ago!

Matt

@JonasTeuwen Get me beer? Nah, I can do that.

Henning Makholm

I.e. before I typed rm some-file * as root instead of rm some-file.*.

Jonas Teuwen

@HenningMakholm noglob?

Henning Makholm

Well, I'd like to have some-file.* work ... otherwise one needs to override so often that it desensitizes one to the override.

Matt

@JonasTeuwen Also, my girlfriend is at a dancing competition.

Jonas Teuwen

18:48

@Matt Hmm.

Matt

No questions for me today : (

Jonas Teuwen

@HenningMakholm In zsh prefixing noglob disables the expansion... so... 8-).

@Matt youtube.com/watch?v=32bVUFshSAo

Also why is it reading /root/.profile?

In my setup it shouts at you: U sure 'bout that bro? Leave the drink

Henning Makholm

@JonasTeuwen Because I was root at the time. Mucking around in the (now late) Postfix configuration.

Jonas Teuwen

@HenningMakholmn Do you have one of the offending commands? I am trying.

Matt

Hi @JasperLoy

user19161

18:58

@GustavoBandeira I am listening to it now. And I see your pic there too.

user19161

@Matt Hey, exams over soon right?

Henning Makholm

@JonasTeuwen The exact offending command was "rm always-cybercity *" -- where the last space should have been a dot.

Matt

@JasperLoy They are over but now I have to write a thesis. In two weeks.

Let's not talk about it.

Transcript for

$Mathematics$ Mathematics