The h Bar

vzn

5:00 PM

@Sᴋᴜʟʟᴘᴇᴛʀᴏʟ you can create any room you want and own it right?

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

Yes

vzn

@Sᴋᴜʟʟᴘᴇᴛʀᴏʟ so whats the problem? agreed it is hard to start new rooms that attract participants. but "not hard" to open them.

ACuriousMind

That's not "power creep" because also being a room owner gives a mod zero extra powers.

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

nvm, I give up

0celo7

@Sᴋᴜʟʟᴘᴇᴛʀᴏʟ I have no love for the mods, but I don't see the issue

vzn

5:03 PM

@Sᴋᴜʟʟᴘᴇᴛʀᴏʟ look, have some sympathy, got into trouble once over on Programming Puzzles & Code Golf & elsewhere... seems to be a bunch of teenagers over there, and the SF&F chat room mods also tend to be pretty heavyhanded at times... =(

ACuriousMind

they need to be heavy-handed after the meltdown that happened there a while ago :P

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

Shog9

vzn

@ACuriousMind heard rumors of that, sounded like big deal but dont know the details

0celo7

I still dunno what happened in SFF

vzn

did they just end up deleting a bunch of chat lines and handing out suspensions?

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

5:05 PM

They froze the room for a week

vzn

@Sᴋᴜʟʟᴘᴇᴛʀᴏʟ lol wow never heard of that before o_O

ACuriousMind

@0celo7 Don't.

vzn

@0celo7 youre so creative sometimes :P

ACuriousMind

...just stop it already.

0celo7

@ACuriousMind Stop what?

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

5:06 PM

Trolling

ACuriousMind

@0celo7 Always searching for a way to drop some comment about "JD". It's not funny, it's childish.

vzn

@ACuriousMind how about more musings/ mediations on hidden variables instead then? :P

ACuriousMind

@vzn I am awaiting your essay ;)

David Z

@0celo7 yes, what @ACuriousMind said. That's inappropriate.

0celo7

Hmm.

vzn

5:08 PM

@0celo7 yeah! "GDP" is acceptable as an endlessly running punchline. but not "JD".

0celo7

GDP is not a punchline...

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

What would you call it?

vzn

this all now reminds me of a Pink song with the line "youre my perfect little punching bag..."

Secret

1

Q: Basic Quantum Entanglement

Quantum entanglement means that multiple particles are linked together in a way such that the measurement of one particle's quantum state determines the possible quantum states of the other particles. But my question is that if we randomly pick up any pair of particles from anywhere, will it be e...

Have to read up how to do a bell test, as it is entirely possible to find e.g. 3 sets of data that are correlated but does not mean they are all entangled

vzn

@ACuriousMind ok fair enough might work on that sometime. ps QM is about quanta

0celo7

5:10 PM

@Sᴋᴜʟʟᴘᴇᴛʀᴏʟ Life.

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

Fair enough

vzn

@Secret physics is still deeply wrestling with an old scientific concept. "correlation does not necessarily imply causation."

0celo7

Necessarily?

When does it ever?

vzn

@0celo7 its a very subtle (zen-like) question at the heart of some deep philosophical questions studied by the ~~Big Names~~ greats eg about "induction".

aka "scientific method"...

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

Ooooohmmm's law ;)

Danu

5:20 PM

Finally got to play one of the most beautiful mates :D

vzn

@Sᴋᴜʟʟᴘᴇᴛʀᴏʟ (lol) hey are you studying physics?

Danu

The most beautiful way to sacrifice the queen :)

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

nice

vzn

was discussing this with a 12yr old newbie. is a pawn move in front of the king considered a weak opening?

Danu

Of course, because I saw this possibility, I misplayed the position and should've actually lost (after Rc8-c7 I'm losing because he takes the knight with his rook at the end)

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

5:24 PM

How well do you do playing against the computer?

Danu

What do you mean?

Obliv

Is it okay to write this calculus like this? $a = \frac{dl}{dc}$ | $b = \frac{{d^2}l}{d{t^2}} = \frac{da}{dc}$ instead of $\int b{dl} = \int\frac{da}{dc}{dl} = \int{a}{da} = \frac{a^2}{2}$ can I write this as $\int b{dl} = \int \frac{{d^2}l}{d{c^2}}dl = \int \frac{{d^2}{x}{dx}}{d{t^2}dx}dx = ?$ is this correct? What would be the solution in terms of $l$ and $c$?

oh i meant to press enter to indent

o well

Danu

The step $\int \frac{d^2l}{dc^2}dl=\int \frac{d^2x}{dt^2}\frac{dx}{dx}dx$ doesn't make sense to me

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

Can you get up into the higher levels?

Obliv

$\int \frac{{d^2}{l}{dl}}{d{c^2}{dx}}dl$ whoops i used the wrong symbols

Danu

5:26 PM

@Sᴋᴜʟʟᴘᴇᴛʀᴏʟ What do you mean by higher levels?

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

The top 5.

Obliv

I MESSED IT UP AGAIN. i can't do anything with 4 hrs of sleep apparently..

Danu

You mean $\int \frac{d^2l}{dc^2}dl=\int \frac{d^2l}{dc^2}\frac{dl}{dx}dx$ ?

@Sᴋᴜʟʟᴘᴇᴛʀᴏʟ Ehh... what are you referring to?

Obliv

no x's. those are meant to be $dl$'

just wondering if its the same thing and gets the same solution or do you have to use a variable in place of the differentials

i didn't even have to multiply by $\frac{dx}{dx}$ that's just a step that would be taken for the solution before it.

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

I mean, I bought a cheap hand held chess player and it crushed my interest in ever playing the game again.

Obliv

5:30 PM

so disregard that last step. just need to know if $\int \frac{{d^2}l}{d{c^2}}dl$ is solvable

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

It was just toooo good.

I turned to checkers :-/

vzn

@Sᴋᴜʟʟᴘᴇᴛʀᴏʟ again sympathize, just lost 5games streak to a new 12yr old player o_O

the good news is, am a good coach =D

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

O_o kids these days

Obliv

a new 12 y/o? He must be a prodigy..

Slereah

3 day week end B)

Thank you Jesus

Hope dying and all wasn't too much of a bother

ACuriousMind

5:33 PM

@Slereah Not 4 day?

Slereah

Nope

No friday off here

ACuriousMind

Poor France :P

Slereah

Good friday isn't good enough

Oh I don't complain

I probably have way more vacation days than you

What with our lazy french work ethics

0celo7

@ACuriousMind I got today off

But not Monday

ACuriousMind

@Slereah Oh, but I have infinite vacation days because I don't have a job :P

Slereah

5:35 PM

Ah yes, that is the best job

I do miss joblessness

Salary was pretty poor tho

ACuriousMind

Well, technically I'm a "full-time student", not jobless, I guess.

Slereah

Eh, I don't miss being a student

John Duffield

@JohnRennie : noted.

Slereah

Exams were pretty shit

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

Hi @JohnDuffield

ACuriousMind

5:37 PM

I don't have a problem with exams. I mean, I could do without them, but they're fine.

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

Do you prefer the lab over exams?

John Duffield

@Sᴋᴜʟʟᴘᴇᴛʀᴏʟ : Hi. Sorry, I forgot to say: I saw your message. Apology accepted.

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

:)

ACuriousMind

Haven't been in a lab for quite some time.

I'm a theorist, remember ;P

Didn't hate the labs as such though, just the instructions and instructors were mostly pretty crap

But I get that no one actually wants to babysit physics students doing experiments that have been done thousands of times already

John Duffield

@skillpatrol : Hi. Sorry, I forgot to say: I saw your message. Apology accepted.

0celo7

5:47 PM

@ACuriousMind have you ever seen a math book omit the () in f(x)?

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

@JohnDuffield no problem

fx could mean f times x, no?

Slereah

I've seen $f_x$ for $f(x)$

0celo7

Wow, an American math book that says fibre

ArtOfCode

@0celo7 that's just weird

Secret

Given

$$a=\frac{dl}{dc}$$
hence
$$\frac{da}{dc}=\frac{d^2l}{dc^2}$$

Integrate both sides, get

$$\int \frac{da}{dc}dl=\int \frac{d^2l}{dc^2}dl$$

Do a change of variables
$$\int \frac{da}{dc}adc=\int \frac{d^2l}{dc^2}\frac{dl}{dc}dc$$
Now use 1st fundamental theorem of calculus on LHS

$$\int ada=\int \frac{d}{dc}(\frac{dl}{dc})\frac{dl}{dc}dc$$

and then RHS
$$\frac{a^2}{2}+C=\int \frac{dl}{dc}d(\frac{dl}{dc})dc$$
And thus
$$\frac{a^2}{2}+C=\frac{1}{2}(\frac{dl}{dc})^2+C$$

Thus it is valid

Danu

5:53 PM

@ACuriousMind Btw, Transistor got a bit boring once I discovered how OP Void +SomethingStrong is :P

0celo7

They also say imbedding

Danu

@0celo7 Ewwww

0celo7

Sachs and Wu you better get your stuff together

@Danu HE uses that term

Danu

HE is crap :)

ArtOfCode

@0celo7 that's just wrong

0celo7

5:54 PM

@Danu That actually offends me

Obliv

@Secret

woops. I meant to say @Secret thank you.

ArtOfCode

@0celo7 your offense offends me ;)

0celo7

"We use the usual swindle for domains of definition"

What does that even mean

oh my god this notation is atrocious

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

A "swindle" is a cheat.

0celo7

they mean they're going to abuse the notation a little

NO why do they define the wedge with an extra factorial, this makes everything worse

@Slereah don't bother with this book

Secret

5:57 PM

Correction:

$$\frac{a^2}{2}+C=\int \frac{dl}{dc}d(\frac{dl}{dc})dc$$

should be

$$\frac{a^2}{2}+C=\int \frac{dl}{dc}d(\frac{dl}{dc})$$

0celo7

I'll read it because my advisor thinks it's good, but the notation is just terrible

Obliv

Yeah I was just about to mention that. Thank you again

Secret

The reason we let the variable a is because nearly no one will write something like

$$d(\frac{d(blah)}{d(blahblah)})$$

Danu

@0celo7 I don't see much use for the book. What should one aim to learn from it? Neither physical understanding or interesting mathematics seem to be priority in that book.

Obliv

lol yeah I know. I just want to see what the relationship between the variables are.

0celo7

5:58 PM

@Danu It's very interesting math

Danu

@0celo7 From what I've heard you talking about in the room, I think we'll have to agree to disagree. All that point-set topology sounds terribly tedious and unenlightening ;)

0celo7

Because I haven't gotten to the good parts

Secret

I like topology, because it is pictorial

Obliv

Wait, isn't $$\int \frac{dl}{dc}{d}(\frac{dl}{dc})$$ supposed to be $$\int{\frac{dl}{dc}\frac{d(\frac{dl}{dc})}{dc}$$

0celo7

@Danu and HE has a lot of material that was expanded upon in later years

so it's important to first understand HE

Obliv

6:01 PM

$$\int {\frac{dl}{dc} \frac{d(\frac{dl}{dc})}{dc}$$ did i type something wrong

ACuriousMind

Mismatched parentheses.

Obliv

oh. thanks. \int{\frac{dl}{dc}\frac{d(\frac{dl}{dc})}{dc}$$

$$\int{\frac{dl}{dc}\frac{d(\frac{dl}{dc}}{dc})$$

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

How much does it cost @0celo7?

0celo7

How much does what cost?

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

HE

Danu

6:03 PM

Stop posting non-compiling MathJax!!!

0celo7

@Danu Chill brah

Obliv

so sorry! it just isn't working... $$\int {\frac{dl}{dc} \frac{d(\frac{dl}{dc})}{dc}$$

0celo7

@Sᴋᴜʟʟᴘᴇᴛʀᴏʟ Last time I checked, $88, why

ACuriousMind

@Obliv You open a bracket after the \intwhich is completely superfluous and you don't close it anywhere.

0celo7

lol

Obliv

6:03 PM

$$\int \frac{dl}{dc} \frac{d(\frac{dl}{dc})}{dc}$$

GOT IT.

my face is red ****

0celo7

you didn't need to post it a bunch of times

What?

I literally have no clue what that means

It $C^\infty$ if there's another $C^\infty$ map?

Secret

@Obliv Nope because there is no differential (the dc) in the integral

thus this is an incomplete expression

ACuriousMind

@0celo7 The point is that you can't define differentiability at the endpoints of a closed interval.

So they define the differentiability on a larger open set containing the interval.

0celo7

Oh, right.

The original $\mathscr{E}$ need not be open...

user54412

@ACuriousMind When I have some down time I might do that. Consider this code golf proposal, which was shot down I think based on their help page. On the other hand stackapps really did alter a reputation value.

0celo7

6:07 PM

That's a bit of a pedantic point though...

Secret

From the previous step
$$\frac{a^2}{2}+C=\int \frac{dl}{dc}d(\frac{dl}{dc})dc$$

You do a chain rule on $\frac{d(\frac{dl}{dc})}{dc}dc$ to get $\frac{dl}{dc}$ as the variable (this is what the a is on the LHS)

0celo7

@Danu HSM guy, would you happen to know why GTM books from the 70s have this ugly diarrhea colored cover?

ACuriousMind

@ChrisWhite Hmm...the code-golf one is not marked status-declined, though

0celo7

Ok now that's just strange.

user54412

Perhaps they decline things the same way I do: ignore them until the petitioners die of old age.

0celo7

6:09 PM

Has anyone seen diff geo presented like this?

Ohhhh, I'm stupid

Obliv

@Secret Yeah I see. I actually cancelled out the dc's as differentials in my work I just got confused for whatever reason..Okay it all checks out.

vzn

any CS fans here? @ChrisWhite spare a click? so )( close =D meta.cs.stackexchange.com/questions/1195/…

user54412

For the last year the university has been trying to get me to take a survey asking how many times I raped an undergrad. At this point though they're only offering 20 bucks and a warm fuzzy feeling for completing it. I'm hoping holding out will make the offer go up more.

0celo7

@ChrisWhite Well, how many times?

user54412

@vzn looks like a statue of Shannon somewhere around this campus

0celo7

6:14 PM

@ChrisWhite The only reason you wouldn't answer is if it's more than 0 times.

user54412

I'm pretty clearly not answering because their offer has been increasing in value faster than any reasonable investment.

0celo7

That warm and fuzzy feeling when you understand crappy notation

Obliv

Hey guys is mass just essentially potential energy and when it transforms itself to pure energy this energy can be related to motion? Is there any form of energy (not potential) that is not related to motion/space?

ACuriousMind

What does "transform itself into pure energy" mean? What is "impure energy"? And no, mass is not potential energy, it's mass. The two don't even have the same unit.

Obliv

I guess photons?

Secret

6:21 PM

will revisit this in the future

Obliv

Well I mean in the case of $E = m{c^2}$ where the energy is lying dormant in the mass internally. Not all potential energies retain the same units. In this case, I'd describe it as E/c

0celo7

@Secret Background?

You literally just plug in the definitions of the smbols

That is, let $f:M\to \mathbb{R}$

Now evaluate $$\gamma_*\frac{\mathrm{d}}{\mathrm{d}u}f$$

Obliv

@ACuriousMind ***$mc^2$

0celo7

where you regard $\mathrm{d}/\mathrm{d}u$ as the coordinate vector on $\mathscr{E}$

it's a terrible way of doing diff geo, but it's not wrong

Danu

@0celo7 I'm not the "history of GR books" guy ;)

@ChrisWhite WTF

0celo7

6:25 PM

@Danu GR books?

GTM are math books...

Danu

Oh, woops misread there

0celo7

now they're yellow with light yellow parts

Danu

MTW $\cong$ GTM

ACuriousMind

@Obliv I don't understand what you're trying to say. Yes, by $E=mc^2$, there is an energy associated to having a mass. What is the question about that?

0celo7

which I don't like as well as the previous design

@Danu MTW is black, not brown.

Secret

6:27 PM

Actually, this inspired me a question: What type of energy is neither potential energy nor kinetic energy nor energy associated to mass?

Obliv

@ACuriousMind i'm trying to internalize what we're trying to say defines energy. I'm under the assumption that it's rooted to motion/space

Secret

For example, thermal energy is basically kinetic energy in the microscopic scale

what type of energy is the energy of a photon, and perhaps other quantum fields?

Obliv

@Secret I asked this question if you wanna look at my profile. Like I read a paper talking about the vis viva controversy with leibniz and newton/descartes. They both were arguing what was more fundamental, energy or momentum essentially so that got me interested in what the definitions of each include.

i say essentially because leibniz didn't use the term energy. He also got the equation wrong for the energy he defined (which was kinetic energy) since he used $mv^2$.

0celo7

> Physical theories are guessed, not deduced; if only deductions were required, every competent hack could be an Einstein or a Feynman.

vzn

@0celo7 who said that? do you know?

0celo7

6:34 PM

@vzn RK Sachs and H Wu in General Relativity for Mathematicians.

Obliv

Yeah that's true. I would give them more credit since guesses are rooted in some kind of intuition/thinking. We're not robots, afterall.

vzn

@0celo7 nice but think new theories are a mix of induction, deduction, brilliance, patience, near-obsession, and luck, etc (but nobody here cares about new theories do they?) :P :(

0celo7

Units are $c=8\pi G=1$. Great.

> The mass of the Earth is about $4\times 10^{-4}$ seconds.

Obliv

Is there an option to send private messages to people?

0celo7

No.

vzn

6:41 PM

@Obliv you can create new out-of-the way chat rooms between you & them.

did newton/ leibniz really argue over energy vs momentum? hadnt heard that one.

@ChrisWhite thx for looking, its Turing statue at Bletchley Park (Museum), undeservedly not well known. vote for it plz? =D

Obliv

Yeah i'll link the paper I read. I think it was along those lines.

nature.berkeley.edu/departments/espm/env-hist/articles/2.pdf it's this one.

vzn

@Obliv interesting thx

0celo7

> Both Newtonian concepts are so misleading that they are worse than useless.

ACuriousMind

@Obliv I'm not a fan of that type of natural philosophy. In modern theoretical physics, energy is perfectly well-defined as the generator associated to time translations.

0celo7

Wow SW come from the Danu school of subtlety!

ACuriousMind

6:46 PM

If you want to know what definition Newton and Leibniz had for the purpose of that controversy, you might be better off asking at History of Science and Mathematics

Obliv

I think the concepts are dated but both modern and classical physics share some fundamental definitions. I want to prove/disprove this.

ACuriousMind

modern and classical are not opposites. In physics, "Classical" means "not quantum" (or "not relativistic" in some cases), not "old".

vzn

@Obliv the paper seems very thorough in attempting to answer something like that question...

Danu

@0celo7 Who said this?

That's really incredibly naive (not to use the word "dumb")

ACuriousMind

@Danu Read one line further :P

Obliv

6:50 PM

I don't believe it covers bases in modern physics. It just focuses on Leibniz's arguments against Descartes. @ACuriousMind Yeah that's true. I meant more that I want to explore the commonalities between them rather than prove/disprove it.

Danu

What, Sachs & Wu?

0celo7

@Danu Correct.

Danu

@0celo7 When it comes to analyzing (historically significant) physical theories, I am indeed a lot more subtle than you might be used to ;)

@0celo7 Wow, as writers of a book of mathematics that makes them really... non-respectable, in my opinion.

0celo7

Their notation makes them non-respectable >:[

Danu

I mean, honestly... Mathematics is nothing but deductions. Are they calling all mathematicians stupid?

0celo7

6:54 PM

@Danu The book is approved by Chern and O'Neil, they proofread the manuscript.

user54412

It's a book titled General Relativity for Mathematicians written by mathematicians -- did you really expect it to have any insight into how physics works?

0celo7

the first proof uses something that i have to prove in my analysis homework

Danu

@ChrisWhite But implying that all deductions are trivial?!

0celo7

small world

user54412

@Danu I get the sense they're implying all physics deductions are trivial.

Danu

6:58 PM

@ChrisWhite They sentence, as it stands doesn't rule out any other purely deductive contexts

0celo7

@Danu Oh and Carroll recommends the book.

Danu

And even then, it's pretty dumb

@0celo7 The book may still be very good!

user54412

Most mathematicians I've met have no idea whatsoever what physics is, since all they've ever seen of it is mindlessly crunching Lagrangians. They honestly think physics is just simplified math for stupid people.

0celo7

@Danu And my advisor, but he's not a physicist.

And he probably skipped the intro.

Danu

In fact, it's on my to-read list ;)

(a long way down, though...)

0celo7

7:00 PM

@ChrisWhite Have they even seen experimental physics?

There's not even math there!

It's math so simple that there's no math!

@ChrisWhite One of my (math) profs said it was disingenuous of string theorists to call themselves physicists.

Obliv

Are force-carrier particles measurable?

Balarka Sen

I have seen jokes about physicists not knowing mathematics on the math chat and laughed a lot on that occasion, but I am not sure how I feel about mathematicians not knowing physics being the hot topic in here. I guess I am biased after all!

Danu

@BalarkaSen Hah. Now the real question is: Who is more ignorant?

Balarka Sen

I'd guess on average mathematicians.

'Cause majority of physicists actually use mathematics in their work.

Danu

Hmm, but at least here on SE you're getting a very distorted impression

Of course all physicists use calculus.

0celo7

7:07 PM

@Danu The right answer is usually "0celo7."

Danu

But much more than that? Hmm...

@0celo7 You're kicking yourself now?

Balarka Sen

@Danu I have no idea of course, but I have found the physicists I have talked to rather appreciative of some math out of calculus.

Speaking of, what happened to @0celo7's face?

Danu

@BalarkaSen Was this limited to the SE crowd? Because you're not getting a good picture of average physicists on here ;)

0celo7

@Danu amazon.com/General-Relativity-Without-Calculus-Undergraduate/dp/…

Balarka Sen

No, not limited to the SE crowd.

Danu

7:09 PM

@0celo7 Ewwww

Balarka Sen

LOL, @0celo7.

0celo7

I know all of the GR books...even the terrible ones :D

Balarka Sen

@Danu Actually now that I think of it most of them were string theorists.

0celo7

From the same prof: "What's so bad about being a mathematician that string theorists insist on being physicists?"

Balarka Sen

I am sure most mathematicians will take that as a compliment.

Danu

7:12 PM

@0celo7 The funding

0celo7

@Danu Yes, that's what he suspects.

@BalarkaSen Well yes.

A mathematician is the one who said that!

@BalarkaSen What do you mean?

You certainly don't think that picture is me :P

@Danu I'm the first one to admit I know nothing...

Balarka Sen

No, that is why I asked what happened to your face.

0celo7

@BalarkaSen I never had my face as my avatar.

Balarka Sen

Sure. It was a cat.

0celo7

Yes, my cat

I'm considering putting my dog as my next avatar

Obliv

7:16 PM

@0celo7 what's so bad about that book?

0celo7

@Obliv There's no point, really.

And a first year undergrad should be able to read something like Zee.

Obliv

@0celo7 Yeah, not really sure what the author was trying to do in helping high school students learn GR..

0celo7

@Obliv Zee's book is perfectly suited for a motivated HS student.

Danu

@0celo7 Naaaah

0celo7

@Danu Not the whole thing, of course.

(There are some difficult parts and the exercises are hard.)

Note: I'm talking about his GR book, of course, I don't acknowledge the existence of his QFT book.

Obliv

7:21 PM

I wonder what would be better for the average person. To study math primarily first and then start applying concepts to the physical world or to learn them concurrently.

0celo7

@Obliv I think you should read a good book on Riemannian geometry first.

At least the first few chapters.

Obliv

Do you need any pre-requisites for that? (Now i'm curious)

0celo7

Yes.

Obliv

I always respected riemann a lot. He was so smart :O

0celo7

I think the first "Riemannian geometry" paper did not even have any proofs in it.

Maybe @Danu knows more

It was all intuition at the beginning

ACuriousMind

7:25 PM

@Obliv You can't really "study math first and then apply concepts to the physical world". Physicists are notorious for doing "sloppy" math and the reason is that a lot of the time the finer subtleties of the math don't really play a role to understand the physics.

0celo7

And he tried to justify Gauss' work in a more general framework

Danu

@0celo7 Depends what you count as Riemannian geometry, probably.

ACuriousMind

And how would you even know which math to study? You don't know what kind of math you need before you haven't started doing physics.

Danu

Nice, recent example of mathematics growing out of physics

0celo7

@Danu I knew what that would be on before I clicked the link.

But the better example is that Riemannian geometry exploded only after 1915.

ACuriousMind

7:26 PM

@Danu We know you like mirror symmetry ;)

0celo7

I can count the number of Riemannian geometers before 1915 on one hand.

@Obliv There are many "good" Riemannian geometry books.

Obliv

@ACuriousMind Well I imagine physicists would decide which maths are important and in what order, to plan out a good curriculum. Yeah I don't think applying math to the real world inspires creativity. It'll almost be like if you have a toolbox and you're just trying to find out which tool to apply where.

I read that I would have to finish learning calculus and thoroughly understand 2D&3D Euclidean geometry.

ACuriousMind

@Obliv But the physicists would all just emphasize the math that's needed in their subfield, which is a lot for some and very little for others. I think it would be a very bad idea to try to teach physicists by first only teaching them math.

And you don't learn "physical thinking" by learning math and then applying it. Physics isn't just applied math.

Obliv

@ACuriousMind Very true.. It's not like physics is a one-way street after all. I guess it could be if we lived longer/indefinitely.

0celo7

What's up with making the LC connection $D$ and not $\nabla$

Jost does this too, it's weird.

@Danu Know of any reason?

Danu

7:39 PM

$D$ for derivation?

It's really the more obvious choice, considering the normal $\frac{\mathrm{d}}{\mathrm{d}}$ notation

0celo7

@Danu when was the $\vec\nabla$ notation introduced?

I think $\vec\nabla f$ is ubiquitous, right?

ACuriousMind

@0celo7 Read the Wiki article.

0celo7

I guess analysts use $Df$

But they're weirdos

@ACuriousMind 1901 apparently

ACuriousMind

Read again.

0celo7

@ACuriousMind It's not in the wiki article

ACuriousMind

7:44 PM

"It was introduced by the Irish mathematician and physicist William Rowan Hamilton in 1837."

0celo7

But one of the links says Hamilton introduced it

Huh

That's a different article

> Proposition 1.1.7. The lightcone $\mathscr{L}_0$ is a lightlike submanifold.

Obliv

Hamilton died in 1865 if youo mean william rowan

user54412

Nothing says Irish like "William Hamilton"

user54412

also, apparently he became a professor of astronomy at age 22

0celo7

@ChrisWhite Shows you how easy astronomy is

Obliv

7:56 PM

Who is the youngest accomplished mathematician/physicist to die? I read that en.wikipedia.org/wiki/Alexander_Friedmann died at 37 D: that sucks so bad..

ACuriousMind

@ChrisWhite Looks like you're a few years late then, hm? ;)

Obliv

to make matters worse he died to typhoid..

0celo7

There's a lot of mathematicians who died young.

Abel and Galois immediately come to mind.

ACuriousMind

Reminds me of this quote: "Ludwig Boltzmann, who spent much of his life studying statistical mechanics, died in 1906, by his own hand. Paul Ehrenfest, carrying on the work, died similarly in 1933. Now it is our turn to study statistical mechanics. Perhaps it will be wise to approach the subject cautiously."

Slereah

@Obliv Galois

Galois died at like 22

And he accomplished more than you ever will

0celo7

7:59 PM

Lol

Obliv

wtf.. he died at 20. that's not fair man. also hey you don't know that give me enough time and maybe a means of living for another 100 years and I'll probably think of something.

0celo7

That's what you think

Once I have control of the nukes, we'll see who can accomplish things

Obliv

@ACuriousMind Is there any reason to believe their suicides were linked to statistical mechanics? o_o spooky

ACuriousMind

@Obliv And they were apparently not the only ones, see here.

0celo7

Mb thermo is the secret of the lizards

Obliv

8:08 PM

@ACuriousMind it looks like Boltzmann had some deteriorating health defects. Arguing a perspective that isn't very favorable to the majority of physicists at the time along with those illnesses seem to be the cause. I really hope that's the case and not that if you take a course in statistical mechanics you're going to be cursed by some ghost that forces you to commit suicide..

Danu

@ACuriousMind For quite different reasons though---Ehrenfest's suicide was sparked by despair over his son, who had severe mental problems. He first shot his son, then himself.

ACuriousMind

Oh, great, so the curse also affects family members.

Obliv

well I guess I'm not having kids if I decide to study statistical mechanics.

0celo7

@ACuriousMind you related to any stat mech people :P

ACuriousMind

No one in my family is a physicist.

0celo7

8:18 PM

no one living, at least

vzn

8:35 PM

1 hour ago, by Danu

@BalarkaSen Hah. Now the real question is: Who is more ignorant?

DanielSank

@Danu Of course what I said only works if you have a large enough sum.

vzn

↑ lol at debate over "whos more ignorant," mathematicians or physicists. or maybe the socratic approach is for all to acknowledge a irrevocable/ ubiquitous/ inevitable "lack of knowledge"... newton himself did so in a famous quote... obviously math & physics is one of the great scientific synergies of the last few centuries, starting even in the enlightenment etc... continuing to scale new heights daily...

Danu

@DanielSank Ah.

I had a fever last night and it was all I could think about, laying awake at ~2 AM :P

ACuriousMind

Oh, your body turned up its own heating in response to the broken one? ;P

Danu

Perhaps... But too late! It got fixed last morning...

ACuriousMind

8:48 PM

yay

Danu

@ChrisWhite Did you ever post that suggestion to make downvotes weigh more heavily?

ACuriousMind

3 hours ago, by Chris White

@ACuriousMind When I have some down time I might do that. Consider this code golf proposal, which was shot down I think based on their help page. On the other hand stackapps really did alter a reputation value.

0celo7

@ACuriousMind hah

biology at work