The h Bar

0celo7

19:03

I still don't know if you know who is a troll or misguided

AngusTheMan

Quick question, what is the difference between extrema, stationary points and critical points?

0celo7

The names

AngusTheMan

cheers

skill patrol

He's a cross between a troll and a crank. The troll part quotes Einstein, while the crank part digs up The Evidence.

FenderLesPaul

@AngusTheMan stationary and critical points are synonymous

but they need not be extrema

Slereah

19:12

stationary is $\dot{x} = 0$

Extrema is stationary but $\ddot{x} \neq 0$

0celo7

Yo I never said there weren't other differences

AngusTheMan

Thanks guys, So the curvature is non-zero with extrema but is zero for stationary ?

0celo7

The names are a difference tho

:P

Slereah

A critical point is way more urgent than a stationary point

"Sir we've hit a critical point!"

2

"ALL MEN ON DECK!"

You won't get that with a stationary point

John Duffield

@vzn : I wouldn't call it "frontier" physics. It's more like contemporary research as opposed to 50-year-old textbook. And some of the stuff I talk about is fairly old stuff, going back to the likes of Einstein.

skill patrol

19:16

and The Evidence.

John Duffield

@skillpatrol : yeah, and the hard scientific evidence. That's real important. Only you wouldn't know what that was if it jumped up and bit you on the arse. Trollboy.

FenderLesPaul

dude how old are you?

skill patrol

Sticks and stones...

John Duffield

@FenderLesPaul : Fifty nine. All grown up. How old are you, kid?

skill patrol

Do you have a degree?

Slereah

19:21

He does not.

FenderLesPaul

I'm 6

John Duffield

Yes. Computer science. Do you have any reputation? Or do you just hang around insulting the people who answer questions?

Slereah

Please @FenderLesPaul

Don't forget the unit.

FenderLesPaul

6 TeV

Slereah

On average I suspect @FenderLesPaul has more positive votes than negative votes, though :p

John Duffield

19:23

I was just looking at his votes. Doubtless they're from the other chatroom trolls.

Slereah

The conspiracy

0celo7

@FenderLesPaul I just told you that to make you feel good. You're more like 5 or even 4.5.

Slereah

Guys you didn't even define a coordinate system

How am I supposed to do anything with those numbers

0celo7

inches

Slereah

Thanks buddies

0celo7

19:28

how can you tell who upvoted

I didn't even upvote it

and I'm the master troll

Slereah

I thought you were my chatroom troll buddy :(

0celo7

+1 :)

Slereah

:D

skill patrol

Who made you the master?

0celo7

gotta help out my fellow trolls

Slereah

19:29

There's at least 9 terrible troll buddies, because that's as low as JD's downvotes go

0celo7

@skillpatrol are you really gonna challenge me

Slereah

Well, the ones that were not deleted

0celo7

DAMN

REKT

minimal homework toinght

skill patrol

Hi @KitZ.Fox

0celo7

@FenderLesPaul if you want to redeem yourself, GR talk

ArtOfCode

19:30

This is a mod-invasion, and I'm issuing multiple charges of not Being Nice. Penalty: a reminder to you all to Be Nice.

Slereah

2cool4school

Will do good sir

0celo7

@ArtOfCode please specify

Kit Z. Fox

@FenderLesPaul I suggest that you don't joke about being underage unless you want your account to be permanently expunged. Happened to one of our users in EL&U chat who thought it would be funny to say she was 10.

0celo7

I'm pretty nice IMO

Kit Z. Fox

@skillpatrol Yo.

0celo7

19:31

but not everyone agrees

Slereah

Maybe you should ask the philosophy SE

0celo7

@KitZ.Fox wait what

Slereah

Is there an ethics SE

0celo7

what is the minimum age for the chat/site?

I'm legitimately underaged

Kit Z. Fox

13

skill patrol

19:32

^

0celo7

ah, my chest hair means I am beyond that

ArtOfCode

@0celo7 See the deleted message up there? That's what brought me here.

Kit Z. Fox

If you are younger than that, I'd suggest you don't advertise it.

0celo7

@ArtOfCode I see

@KitZ.Fox a month away from 18

I can almost taste the freedom

skill patrol

Viva Las Vegas at 19?

Kit Z. Fox

19:33

@ArtOfCode Next time, give them the kittehs.

ArtOfCode

@KitZ.Fox ... not the kittehs

skill patrol

:D

Kit Z. Fox

@ArtOfCode Yes. Give them all the kittehs.

ArtOfCode

Hi there @WadCheber

@KitZ.Fox They surely couldn't survive such a penalty.

Kit Z. Fox

That's not my problem.

Wad Cheber

19:34

@ArtOfCode Howdy. Just came to watch the hammers.

You guys are naughty.

Slereah

ArtOfCode

@WadCheber You've missed the hammering, I'm afraid. Mjolnir has been put away again.

Wad Cheber

Tsk tsk.

skill patrol

I am the one who started this whole thing and I take full responsibility. . I am sorry

Slereah

for shame

Wad Cheber

19:35

@ArtOfCode I always miss the fun.

skill patrol

:(

Kit Z. Fox

Surely not you, @skill

0celo7

only one is naughty

ArtOfCode

@skillpatrol No worries on your part; you're not the one who took it to the level that brought the mods here.

0celo7

the rest are easily trolled

Wad Cheber

19:35

You should be ashamed of yourselves.

0celo7

for once I feel like I'm innocent

ACuriousMind

@0celo7 I can be naughty, too ;)

Wad Cheber

What do you think this is, mathematics chat?

4

0celo7

@ACuriousMind :O not in class

Kit Z. Fox

Who is the local mod?

0celo7

19:36

we have none

we are a lawless bunch

skill patrol

DavidZ

Slereah

Isn't it @Danu?

Kit Z. Fox

That explains your crappy star wall.

Slereah

Or am I overestimating his power

ArtOfCode

DavidZ, Manishearth, Qmechanic, dmckee

0celo7

19:37

our star wall is our pride and joy

Slereah

Ah yes

ArtOfCode

@0celo7 clears stars

0celo7

you dare question it?

@ArtOfCode why would you do that

Kit Z. Fox

Can't be. One star per line is not much representing.

ACuriousMind

Jul 20 at 14:23, by 0celo7

Screw you star person + star person # 2

0celo7

19:37

our star wall is seriously a part of the community

ArtOfCode

@0celo7 Power corrupts.

ACuriousMind

You question it yourself regularly :P

0celo7

@ACuriousMind well those guys are asshats

ArtOfCode

Total power corrupts totally

0celo7

everyone else is nice

Kit Z. Fox

19:38

So your mods don't frequent chat?

0celo7

-2

Q: The electron is a 511keV photon going "round and round." How does this work?

I'm curious about the properties of the electron as given in this PSE post. I always thought the electron was an excitation in the electron field. Apparently that's not true and it is a photon going round and round in a Dirac's belt configuration. I have some questions regarding this: How does ...

Wad Cheber

Screwing is for screwdrivers, not people.

2

ACuriousMind

@KitZ.Fox They usually do

Slereah

They do, just not that often

0celo7

this is how bad we get

Kit Z. Fox

19:38

Yeah, OK.

Wad Cheber

Well, both, but you know what I meant.

yuggib

@KitZ.Fox one is flying to greece now

Slereah

I guess @dmckee and @Qmechanic are the most common ones?

ACuriousMind

@KitZ.Fox You can see Qmechanic lurking in the background right now ;)

0celo7

does Qmechanic read everything

or does he just pop in every now and then

Slereah

19:39

Who knows

Kit Z. Fox

doesn't matter, I was just wondering.

I wouldn't normally just run in and start shouting.

Slereah

As long as he has not the power and the will to ban JD, it matters little

ArtOfCode

And here comes @dmckee. My work is done.

Kit Z. Fox

Generally, when I show up, it's to distract and flatter.

ArtOfCode

@Slereah He's already taking a short break.

0celo7

19:40

@Danu GDI Lang wants to be called by his first name...I can't do it

Readinglist ++

ACuriousMind

@0celo7 lol

Slereah

who cares about neutrons

skill patrol

This is clearly an insult and I apologize.

29 mins ago, by skill patrol

He's a cross between a troll and a crank. The troll part quotes Einstein, while the crank part digs up The Evidence.

0celo7

he's like 35, I can't call him by hist first name

Slereah

They can't even stay in place for 20 minutes

0celo7

19:41

that's just weird!

random people in here...

hey everyone!

Slereah

Although neutrons are decent enough that you can treat them with the sigma model

Hosch250

@0celo7 Hey.

Slereah

which is nice

0celo7

I'm the nice once. Watch out for that @Slereah fellow

skill patrol

You can suspend me now

0celo7

19:42

He's a homewrecker

Hosch250

I came to see the stars. We have a pretty good star wall in the 2nd Monitor too.

Slereah

Well, @0celo7, don't forget

Sep 1 at 22:24, by Slereah

(I only live for revenge)

Hosch250

If you don't want random people in your room, don't flag things.

0celo7

oh jeez

hello @MadScientist

ArtOfCode

I count 6 mods in here.

Slereah

19:44

Let's all act innocent

0celo7

::tries not to f up::

user61230

@Slereah [narrows eyes]

0celo7

I would say something sarcastic, but since there's no way to appeal bans~~

Hosch250

I count 7.

Slereah

So mods, why didn't that motion to reduce the weight between upvotes and downvotes pass

skill patrol

19:45

3 mins ago, by skill patrol

You can suspend me now

ArtOfCode

@Hosch250 You'd be right. I missed one.

Slereah

It seems pretty exploitable

0celo7

indeed, a certain you-know-who has too much rep for BS answers

ArtOfCode

@0celo7 Careful...

0celo7

note, mods, that I cannot be mean towards a hypothetical person

Slereah

19:47

[insert-here-the-user-who-shall-not-be-named]

0celo7

indeed, IDK who that is

skill patrol

13 mins ago, by skill patrol

I am the one who started this whole thing and I take full responsibility. . I am sorry

0celo7

@skillpatrol REPENT

skill patrol

Shhh...

yuggib

@skillpatrol As a penance, you have to produce a ten pages essay on quaternionic quantum field theory for the end of the week

Slereah

19:49

Noooo

skill patrol

....I'm waiting for the axe to fall

Slereah

There seems to be a secret society of physicists dedicated to doing quaternionic physics in a journal

ArtOfCode

@skillpatrol 999999999 hour suspension

Slereah

It's quite amazing

yuggib

And just to be more fun, you would have to set the theory in the Solovay model of ZF+DC where all reals are measurable and not in ZFC.

Slereah

19:50

Like there's a journal specifically dedicated to quaternions

Good riddance, who needs non-measurable sets

yuggib

@Slereah But you don't have the full axiom of choice...Hahn-Banach...

Slereah

What's the worst consequence of that

Sets without cardinalities?

Bah

It's all the worst sets

Wad Cheber

@Slereah I read that as "quartermelons". Now I won't be happy until I eat a nonexistent fruit.

yuggib

Hahn-Banach is at the heart of functional analysis

Slereah

@WadCheber : There is actually a mathematical object called a watermelon

FenderLesPaul

19:53

@KitZ.Fox what?

Slereah

arxiv.org/abs/math/0307204

Wad Cheber

@Slereah I need a quartermelon.

FenderLesPaul

my age is literally on my profile

Slereah

"A watermelon is a set of p Bernoulli paths starting and ending at the same ordinate, that do not intersect."

FenderLesPaul

@0celo7 can we do GR talk tomorrow night? I have to read sections 2 and 3 of the new Maldacena paper for group meeting tomorrow afternoon

Slereah

19:54

@yuggib I'm sure some mathematician somewhere has done a ~C version

yuggib

@Slereah nope

not that I know of

Slereah

Constructivism is like a math cult

They want to rebuild the whole world with constructive axioms

yuggib

@Slereah that does not even cover all usual analysis

Kit Z. Fox

@FenderLesPaul I don't know what to tell you except what I told you. There are special procedures for deleting underage accounts, so it's not a joke you want to make, just in case someone takes you seriously.

Slereah

Do you also have to be human to hold an account

(I am secretly a dog)

(over 13)

0celo7

19:55

@FenderLesPaul Tsk.

Kit Z. Fox

@Slereah No, I don't think that's required.

0celo7

I'm going to lose interest in GR again

Slereah

quite an old dog

0celo7

this is all your fault

Kit Z. Fox

@Slereah In dog years or human years?

Slereah

19:56

Who knows

0celo7

@Slereah you sound like you know who

Wad Cheber

@Slereah You're going to die soon.

Slereah

I'm a dog, I can't count

Wad Cheber

I'm sorry to be the one who told you.

Chances are, your owner will murder you and call it merciful.

Slereah

Constructive analysis

In mathematics, constructive analysis is mathematical analysis done according to some principles of constructive mathematics. This contrasts with classical analysis, which (in this context) simply means analysis done according to the (ordinary) principles of classical mathematics. Generally speaking, constructive analysis can reproduce theorems of classical analysis, but only in application to separable spaces; also, some theorems may need to be approached by approximations. Furthermore, many classical theorems can be stated in ways that are logically equivalent according to classical logic, but...

See?

I knew it

You can always count on constructivists to have their own versions of math theorems

skill patrol

19:58

Did anyone get suspended @KitZ.Fox?

yuggib

Look, I have read (part of) the constructivist book by bishop

Slereah

Constructivism is the math equivalent of pilot wave theory

yuggib

so I know what it is about

it is not much developed

Slereah

Same as pilot wave theory, yes :p

that's the problem when you do marginal stuff

You are still just one man

yuggib

interesting idea, but I prefer an universe with choice

and excluded middle

Slereah

19:59

Well constructive math has choice!

skill patrol

We miss you in the EL&U room @KitZ.Fox

Slereah

Just finite choice

yuggib

much more theorems are provable

maybe also countable choice

Slereah

maybe Iunno

yuggib

not enough for many interesting results

John Duffield

20:01

So, who wants to talk about... gravity!

Slereah

Nah we're good.

yuggib

the greek is online...

skill patrol

Ditto

0celo7

oh he's in ~~a Greek~~ Greece all right

@JohnDuffield sorry, I don't understand the mathematics of higher physics

Slereah

So anyway

In thermodynamics, what is the $\delta$ they use

Like what does it correspond to, mathematically

John Duffield

20:04

@0celo7 : sorry, I wasn't asking you.

Slereah

They told us back then, but we did not have the mathematical baggage to understand it

0celo7

@JohnDuffield aww

John hates me ;'(

yuggib

@Slereah nice question; maybe a variation (as in calculus of variations)?

0celo7

@Slereah exterior derivative

Slereah

It is written as an "inexact differential", but what does that mean

skill patrol

20:06

An irreversible change.

Slereah

Is it like a form that is not exact

AngusTheMan

@JohnDuffield I have a question about gravity related things... as a COMPLETE newbie to both chat and gravity, here goes. Why does the Einstein-Hilbert action require higher order dependance on the field? (unlike normal mechanics action principles)?

Slereah

"It is contrasted with the concept of the exact differential in calculus, which can be expressed as the gradient of another function and is therefore path independent"

It does seem very much like the notion of a 1-form that is not exact

But I never found anything expanding on it

yuggib

If it is a differential form, which is the manifold

?

not so convincing

Slereah

That is my question indeed

AngusTheMan

20:09

@yuggib Do you mean what is the manifold for thermodynamics? They are contact manifolds

Slereah

I suppose some manifold of the thermodynamical values

AngusTheMan

Symplectic manifolds are even dim ... these are od

odd

John Duffield

@AngusTheMan : it's because the gravitational field is the reaction to action h.

AngusTheMan

they have a contact structure

Slereah

@AngusTheMan : Are the $\delta T$ and such 1-forms in those?

AngusTheMan

20:10

@JohnDuffield Do you mean action as in functional? (I have zero experience as i say)

@Slereah I am really not confident as I am learning that sort of stuff myself atm ... but aren't variations in functions on a vector space of smooth paths vertical endomorphisms ?

Slereah

You'll have to ask the more mathy people here!

AngusTheMan

like in classical mechanics where you can define the action principle as a tangent lift

Slereah

@ACuriousMind, this one is for you!

AngusTheMan

yeah, please don't quote me haha

Slereah

Also probably don't ask @JohnDuffield

John Duffield

20:14

@AngusTheMan : I mean action as in E=hf. See the depiction of electromagnetic four-potential in the bottom half of the picture here. Above the A with the blue vertical arrow, the squares are flattened to rectangles. This flattening gradually reduces. Think of that as depiction of Ricci curvature.

Slereah

(I would describe why you should not but mods are here so I can't be mean)

AngusTheMan

I'll see myself out ...

Slereah

(I mean ask JD)

AngusTheMan

@JohnDuffield Thank you for the answer, I will give it some thought.

0celo7

@AngusTheMan wtf does that mean

AngusTheMan

20:17

@Ocelo7 what mean?

John Duffield

@AngusTheMan : IMHO the important thing to appreciate is that field is the derivative of potential, and the photon has an "active gravitational mass". Like any concentration of energy, it causes gravity. Have a look at electromagnetic geometry.

skill patrol

Did you do any graduate work in computer science @JohnDuffield

Kit Z. Fox

@skillpatrol Well, I hang out in The Overlook these days.

For any of my old friends who miss me.

skill patrol

I wish I had more time to hang out there :(

I even had to cut out ELL

John Duffield

@skillpatrol : yes. I worked in my department for a while. But then I got a software house job.

skill patrol

20:28

Programming at home sounds ideal.

John Duffield

All: this depiction of a gravitational field is back to front. It doesn't pull in. It pushes out.

Slereah

I do hope to do telecommuting someday

That way I can get a puppy~

John Duffield

Remember: a puppy is just for Christmas.

0celo7

lol what

vzn

@JohnDuffield curious, what language? do you have CS edu bkg?

hwlau

20:35

What does it mean of "the coupling is neither too short-ranged nor too long-ranged"?

Slereah

Context?

hwlau

lattice

John Duffield

@vsn : I have a computer science degree. I've done lots of languages. I remember Fortran!

skill patrol

BASIC too?

John Duffield

Yes I did BASIC years back, though not at work, only fooling around at home. But besides, the languages were never any problem. The issue was the massively complex systems. When you can understand them, stuff like gravity is relatively easy to understand.

Gotta go I'm afraid. Bye ya'll.

skill patrol

20:44

Later pal.

Slereah

Apparently he does not understand massively complex systems

vzn

@Slereah huh. physics seems like a "massively complex system" :|

Slereah

(the joke is he does not understand gravity)

vzn

the words "adversarial tone" seem to apply (to say the least).

but he seems to have earned 3.7K in only 5mo, quite a feat. (or a nonringing endorsement of SE rep system...)

Wad Cheber

@vzn Psshhht.

Slereah

20:49

Yeah, I would advise you to give a closer look to the details of this reputation

And to investigate how the reputation system works

Wad Cheber

<--- 15k on SF&F in 5 months, including a loss of 5k to bounties, and a loss of 14k to the rep cap. And I'm a moron.

If rep meant anything, that would be ridiculous.

Slereah

so @WadCheber

vzn

ah SF&F have hung out there on chat in past. hardnose mod(s) at the time. :(

Slereah

What is the best science fiction

Wad Cheber

My all time biggest loss to the rep cap is 1,600 in a day.

@Slereah Howard the Duck, the movie.

vzn

20:52

@Slereah the matrix ofc! esp wrt physics :)

Slereah

I tried watching it, but towards the end it was a bit hard

Wad Cheber

I'm actually not a big fan of science fiction.

vzn

@WadCheber lol, so whats left? "F"?

Slereah

My favorite incarnation of Howard the Duck, btw

Wad Cheber

@vzn I'm even less of a fan of fantasy.

Slereah

20:54

But then what do you love :O

Wad Cheber

I got rep by virtue of Star Wars and Tolkien, for the most part.

vzn

WC so then whats left, S&M? :P

Slereah

Well both of those are fantasy :p

Wad Cheber

And I was joking about HtD

Slereah

I gathered, yes

Wad Cheber

20:55

@Slereah Yeah, but I've never seen Star Trek, Harry Potter, etc.

I guess I just get by on my charming personality.

vzn

just bought an art of star wars book few wks ago at newsstand. :)

Slereah

Have you seen the Star Wars Holiday Special

How would you rate it on a scale of 1 to -5

Wad Cheber

@Slereah I'd rather not talk about it.

Slereah

What about Tom Bombadil then

Do you feel up to talk about it

Wad Cheber

@Slereah The only rating that fits it would get me suspended.

Slereah

20:57

Tom Bombadil's Song, Hey Dol! Merry Dol!

►

Wad Cheber

@Slereah I like Tom. But I understand why they always leave him out of movie adaptations

Slereah

I used to have a friend that was mad that they left the heroic adventures of the pony in LotR :p

Wad Cheber

I actually started reading Tolkien because of SF&F.

@Slereah BILL!

Bill is pretty cool.

Not much of a story there though.

Slereah

I am a more Warhammer fellow myself

I tried reading LotR but snore

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