Mathematics

2:04 PM

Hello hello helo

Silent huh

@JasperLoy Thanks.

anon

2:27 PM

did not get nearly enough morphine to get high

I see you are quoting Jasper's statement to Matt, but I don't know why you are addressing it to me.

That was a joke :-D

to see if you were high

2:47 PM

3:13 PM

When I first saw morphine given to injured soldiers, I thought it was a medicine, then later after watching more movies I came to conclusion that it is an effective pain killer. Now I realize that it also gives "high".

@MattN. that gives me an idea how to deal with messages from J.Lo

@JonasTeuwen Yes, that's right. Well, maybe "stressed out" is more accurate. I am busy, too, but that is usually not a problem.

@Ilya Oh my, what have I done... : /

@JasperLoy Btw, "huge" is a bit of an exaggeration since I have a bunch of others on ignore with a much bigger output volume. So rest assured: it's nothing personal.

@Ilya Hi, I think your message is a bit insensitive. You could have silently put him on ignore whenever you wish. Why to say it in public, that too in a message to a third person, unless ofcourse if you wanted to insult him.

@MattN. I guess, you're also ignoring me sometimes - based on this criterion :)

I ignore myself sometimes :-)

The problem with people is that they don't have a sense of humor. Out in the real world you will not survive without some sort of sense of humor.

Hi @HenningMakholm

example^

3:30 PM

Hey @Skull : nice to see you after a while

@RajeshD Nice to see you too Raj :)

BTW @HenningMakholm is an example of someone with a good sense of humor.

3:44 PM

gtg bye

@Ilya No actually, you're rather quiet.

bul

?

I'm as quite as a fish

bul

: D

3:54 PM

:)

Sorry, shouldn't be here, got to go again. bbl

@Ilya What does a fish know of the water that he swims in all his life?

Jackass is being willfully disruptive now, I think. Bleh. Is it so bad if he leaves?

3

@J.M. Jackass?

@Ilya Well, it's the second or third thread in meta that has been opened about him...

I mean, it can't be that he's stupid...

4:07 PM

I'm off MSE these days

almost completely

Oh, sorry about that. :|

This last meta thread just set me off.

(Unrelatedly, I'm cutting down too, for a while. Posting on the site is starting to feel more like work than fun these days.)

Hello everyone

hi

@Szabolcs Hey.

I was wondering, given a "nice" scalar function in 2D, $f(x,y)$, it there a simple way to construct from it some vector field with zero divergence?

The emphasis being on simple.

4:14 PM

@Szabolcs This is for that hedcut thing, I take it...

Szabolcs

@J.M. You're good :-)

I was wondering, if I take the gradient vector, normalize it, and rotate it by 90 degrees, is that going to be fine (zero divergence)?

okay, I think I answered my question

This sounds like something they'd be studying in fluid simulations...

Szabolcs

yes, exactly

isn't that how you guessed it was the headcut thing? I want to distort a point pattern with an interesting flow that's related to the image.

I haven't checked, but the CFD literature is the first place I'd be checking for hints.

Old John

@J.M. Agreed - he seems to have become a deliberate troll in the last few days :(

4:20 PM

@Szabolcs Yeah, have the line detection algorithms work on the image first and take it from there. Fine strategy.

Szabolcs

4:34 PM

Stokes stream function

In fluid dynamics, the Stokes stream function is used to describe the streamlines and flow velocity in a three-dimensional incompressible flow with axisymmetry. A surface with a constant value of the Stokes stream function encloses a streamtube, everywhere tangential to the flow velocity vectors. Further, the volume flux within this streamtube is constant, and all the streamlines of the flow are located on this surface. The velocity field associated with the Stokes stream function is solenoidal—it has zero divergence. This stream function is named in honor of George Gabriel Stokes. Cylin...

It seems that's only for cylindrically symmetric flows

Yes, a bit limited...

@J.M. Who?

@MattN. That guy being discussed in meta for quite a while now...

I just figured that if I want to talk to you I can do it in private : D

I see.

@MattN. Bah, you're exploiting my abilities... :D

4:45 PM

@J.M. : )

bbl

5:06 PM

Hm. Live updating magically started working again. That's too bad.

What browser and OS are you on, Dylan?

Well I just updated to Safari 6. Maybe that's done it.

Still on OS X 10.7. Apple seems to have botched sending out upgrade codes for 10.8.

Oh. When I thought the live updating was gone, I was on Opera. When I used Firefox again, then that feature showed up.

I guess it's a browser thing.

@J.M. Did you see my meta post?

@DylanMoreland When did it?

@robjohn Right after installing the new Safari. Maybe they messed something up WebKit-wise.

5:18 PM

@DylanMoreland Perhaps I need to update Firefox. Mine seems to have stopped yesterday.

Hahhh. So I noticed that some of my teaching reviews were clearly intended for another section being taught at the same time. And they were horrible. The registrar claims that there's nothing they can do to fix this.

Oh joyous, 10.8 finished downloading.

@ZhenLin Ah, cool. I'm still waiting on my code...

I enjoy new operating system installation to an unreasonable degree.

A fancy new Mac for you then?

@J.M. So in this starred post are you referring to a certain Mortal Kombat user

I feel like he's gotten slightly more agreeable. Still shotguns questions up a bit much, I'd say.

5:23 PM

@DylanMoreland Nothing they can do? Really? So you have to live with the after-effects of a mistake, and that's all they can say?

@robjohn It's pretty cool.

@DylanMoreland I would be more upset than you seem.

I'm getting there :)

@J.M. I assume you've seen that I answered the question you pointed out to me.

@ZhenLin Yeah. It had been five years. I figure once I get two versions behind on the OS (couldn't install Lion on it, already) it's time to move on.

5:33 PM

@robjohn I have upvoted your fine answer when I first saw it.

@robjohn which?

@DylanMoreland Five years is a long time. And the latest round of hardware looks very nice. Good timing!

@J.M. this one.

It's just what Dylan and I were talking about.

@DylanMoreland Yes. "Slightly" is a bit much, methinks...

Asaf gave a very useful suggestion :-|

Well, now I have. As I said, at least on Ubuntu, the live updates work on Firefox, but not on Opera.

(which is why I'm using Opera now)

5:35 PM

It works for me in Firefox 14.0.1.

@ZhenLin I wonder how big the update is. I am tethered on my iPhone, so I don't want anything too big.

user19161

@robjohn Some people like to stay on the ESR. But using FF10 does not give full functionality to some sites like say Blogger.

@JasperLoy I'm using 11.0

The full download is 31MB.

user19161

Also, anyone who feels my output volume is too big, please feel free to ignore me! But if I make you upset, please tell me!

5:38 PM

@ZhenLin That's not bad at all.

I remember the days when Firefox was hailed as being small... I think back then it was less than 10MB!

user19161

Chrome is quite a big download too, and on Linux you need to install a whole bunch of dependencies to make it run.

Hm hm, someone is asking lots (> 1) of Riemann surfaces questions today.

@ZhenLin Wow. That was a loooong time ago. About six years, eh?

@JM I've used Firefox since two names ago! :p

5:47 PM

@ZhenLin Well, there's still a Mozilla apparently, so Firefox is more a fork than anything, right?

user19161

On Debian it is called Iceweasel instead of Firefox. The logo is different too.

@JasperLoy That's just because of clashes in licensing... kinda nuts, I think.

@JM Well, actually, I'm referring to the fact that it used to be Phoenix and Firebird.

I think I started with Phoenix 0.7...

user19161

@J.M. The problem is that backports in Debian seems broken. I can't seem to get Iceweasel 14 on Debian, only 10. So if we want 14 we may have to unpack pure FF ourselves.

@ZhenLin Ah. That I have forgotten... I had been using Mozilla and Navigator alternately back in the day, and then suddenly boom, hey try Firefox!

5:50 PM

@JasperLoy Technically, Firefox-branded Firefox can only be distributed by the Mozilla Foundation, or something like that.

Oh, I used Mozilla for only a short while. I forget for how long.

user19161

@ZhenLin Hmm, I think they must satisfy some requirements. Most Linux distros actually use "Firefox".

Perhaps they distribute a bit-for-bit identical copy, as opposed to making their own build.

@JasperLoy It's something in the licensing terms of Debian that clashes with the terms by the Mozilla Foundation, so...

I have a Firefox-branded local build on my Linux box, but I am informed that I am not allowed to distribute it...

@ZhenLin I think so. I like the new Airs a lot, and they're reasonable priced unlike before.

Firefox has kind of lost its way, I feel.

user19161

6:00 PM

@DylanMoreland What browser do you like?

I know of at least two people still doggedly sticking with Firefox 3.x ...

I like Safari. I've never used it on Windows — it might not be so good there.

And the new version incorporates two of the things that I preferred in Chrome, so that's nice.

Hm, 10.8 has a whole new set of desktop pictures and gets rid of the old ones. :(

But they are beautiful, at least.

user19161

@ZhenLin Erm, you know desktop pics can be changed right? But of course I also like the default ones to be nice. :-)

@ZhenLin >Not using pictures of dogs.

6:07 PM

I use a slideshow of the stock backgrounds. :p But they changed the stock pictures!

@ZhenLin nowhere else to grab them from?

user19161

I usually use plain blue background. My favourite is "steelblue".

@JM I have backups, of course.

user19161

I see that we have become more cryptic about some user, using a word instead of two letters to refer to him...

user19161

But I think it's OK to use the two letters to refer to him...

6:13 PM

I don't understand. I thought porton did super formal algebraic stuff that no one knows about. But he doesn't seem to know any category theory.

Everyone's different, I guess.

user19161

Of course, there are over 9000 branches of mathematics!

@DylanMoreland People who take a hands-on approach generally won't encounter category theory!

user19161

@ZhenLin But most grad algebra texts today cover categories quite well.

I wouldn't call what he does algebra...

user19161

The category theory is not necessarily in a separate chapter but is spilled all over the place.

6:16 PM

I have no idea what to call what he does.

What is a funcoid

Something involving a filter on a powerset...

Ed Gorcenski

This is the greatest line in any question ever:

"I have recently come across the concept of 'eigenvectors'"

user19161

@EdGorcenski Well, OP may not have a background in math...

user19161

Actually, it's not really funny at all.

Ed Gorcenski

S/he does not. However, I do not begrudge the OP that; as I have an engineering background, my co-workers and I often joke about how frequently eigenvectors come up and get used as seeming magic wands

6:21 PM

@EdGorcenski Didn't know about them until I was studying math on my own, so... :)

I recently came across the word "eigensheaf". Mind-boggling...

user19161

You must know MSE is for people studying math at all levels.

user19161

So an elementary school kid like me is here too.

Ed Gorcenski

So the phrasing of it seemed very a propos in a number of ways.