The h Bar

DanielSank

12:20 AM

You guys are all crazy.

@EmilioPisanty thanks for that octopus article.

@EmilioPisanty Yes, this is what happens when volunteers write an encyclopedia.

0celouvsky

@DanielSank hmm?

@EmilioPisanty the book I'm reading writes $\Psi$DO

I don't understand why they don't call them "pseudo"s

makes much more sense

might be some historical nonsense

0celouvsky

12:36 AM

@ACuriousMind What is a "universal algebra?"

ACuriousMind

@0celouvsky Don't know anything of that name, closest is the universal enveloping algebra of a Lie algebra

0celouvsky

@ACuriousMind Gilkey calls the exterior bundle $\Lambda (T^*M)$ the "universal algebra generated by $T^*M$ subject to the relation $\xi\wedge\xi=0, \xi\in T^*M$"

I obviously know what $\Lambda(T^*M)$ is

ACuriousMind

Probably his name for "free algebra"

0celouvsky

Free algebra?

Like a free group?

ACuriousMind

Yep.

You know the "free algebra" probably better under its moniker "tensor algebra" ;)

0celouvsky

12:41 AM

@ACuriousMind So just tensor algebra subject to a relation.

ACuriousMind

Yes

0celouvsky

That's...exactly what I picture $\Lambda T^*M$ as.

Nothing new here.

@ACuriousMind This is probably a stupid question but why doesn't de Rham cohomology change if we take $\Bbb C$ coefficients?

Lord Fourier demands $\sqrt{-1}$ so Gilkey's cohomology is over $\Bbb C$.

ACuriousMind

How should it...change?

0celouvsky

@ACuriousMind Why doesn't $\chi(M)$ depend on the type of coefficients used?

idk, I said it was a stupid question

ACuriousMind

Are you worried that you might have $H_i(X;\mathbb{R}) = \mathbb{R}^n$ but $H_i(X;\mathbb{C}) \neq\mathbb{C}^n$?

0celouvsky

12:47 AM

for example

ACuriousMind

Then the universal coefficient theorem saves you

0celouvsky

Oh nooooo

wtf does any of that mean?

ACuriousMind

Alas, I think for the reals and the complex numbers it's much simpler

Just look at the quotients you're taking in the deRham cohomology - all that "taking coefficients in $\mathbb{C}$" does is tensor both closed and exact real forms with $\mathbb{C}$

Now observe that $(V\otimes \mathbb{C})/(W\otimes \mathbb{C}) = (V/W)\otimes\mathbb{C}$ for real vector spaces and you're done

0celouvsky

lol

what?

why?

ACuriousMind

You can just write down the isomorphism

0celouvsky

12:51 AM

I just got a text message from the IRS

ACuriousMind

@0celouvsky That...sounds suspicious.

0celouvsky

@ACuriousMind I don't even know what $V/W$ is, how do you expect me to write down an isomorphism?

ACuriousMind

@0celouvsky It's a quotient

0celouvsky

I was joking.

ACuriousMind

I couldn't tell :P

0celouvsky

12:52 AM

But I don't actually know what the iso is :P

@ACuriousMind I guess one picks a representative in the LHS then tries to get it into a representative of the RHS.

But that's not really writing it down

is...that what you mean?

Emilio Pisanty

@DanielSank no worries

I still don't see why you prefer octopi to squid, but to each his own

Plus if it was squid you liked then you'd have the Bruce Schneier Weekly Squid Blog Post to enjoy

Ramanujan

1:50 AM

Hello

Secret

3:07 AM

@Runlikehell This is true if the bullshit filter is too weak. dmckee's response below spelt that issue out nicely

Indeed, that's what good textbooks, papers of authors that has a lot of experience in a subfield is for. Besides being a core area to reference to for a subfield, it trains the bullshit filter in said subfield

What I have noticed in some research groups is that even when the group is experienced enough (hence have strong bullshit filters), they tend to cite papers within a certain group of authors alot, and this can limit the scope of ideas they can access to for their research

Back in my honours where I am midway through, I have found a paper that is outside of the usual group of authors the research group cited. After they checked the paper, they found the paper is quite good and they add that to their collection of papers they typically refer to

0celouvsky

3:42 AM

@SirCumference How are you my friend?

Sir Cumference

@0celouvsky ...good, you?

0celouvsky

I'm well. Why the dots?

Sir Cumference

I dunno, never heard you say "my friend" to anyone here

0celouvsky

I was in a good mood.

Sir Cumference

That's good. Something happen?

loltospoon

3:44 AM

Hey everyone

Could I get some advice?

0celouvsky

To put me in a good mood or why I'm now not in a good one?

@loltospoon ask away

Sir Cumference

@0celouvsky Both

0celouvsky

@SirCumference Many things for the first; you second guessing me for the second.

loltospoon

I am about to finish my undergrad degree in physics but I don't think I'm going to pursue a grad degree in it

Sir Cumference

@0celouvsky Sorry .-.

loltospoon

3:45 AM

So I need to pick one more STEM elective to finish of my degree

What do you all think I should take in order to be able to find a good job in a STEM field?

Anonymous

:36599933 Whoever told you that is useless.

loltospoon

I plan on applying to FB, IBM, Amazon, Google, SpaceX, and Tesla

0celouvsky

FB is a globalist hive

loltospoon

I can choose any math, science, computer science, engineering course

0celouvsky

@blue Quantum mechanics is wrong

loltospoon

3:46 AM

but I need something that will help me in any of these companies (or any other new-tech company)

0celouvsky

Everyone knows it but they've invested too much to back out now

It's all about that funding

Anonymous

@0celouvsky Everything is wrong. That doesn't mean we stop working on it.

Anonymous

No theory is perfect as they say.

Sir Cumference

What the hell?

Ugh, my cousin has my phone

Fawad

:36599980 let me star it xD

0celouvsky

3:48 AM

cousincide now

Sir Cumference

Yeah no...

Anonymous

@SirCumference Let's chat with your cousin then..give the phone to him/her

Anonymous

:-P

loltospoon

Soooo

any advice?

Sir Cumference

1 min ago, by Sir Cumference

Yeah no...

Anonymous

3:51 AM

@loltospoon The companies you stated hardly take in physics undergrads...for jobs i.e.

Anonymous

AFAIK Google and FB take in mostly software engineers

Anonymous

Though google might be having some side projects

loltospoon

Well, I'm hopeful because of 2 reasons: A) I'll have a broad range of skills that I can present and B) I sat in on a webinar that showed that 70% of physics undergrads go into the private sector

0celouvsky

google has interdimensional stuff

loltospoon

Also, I read somewhere that physics majors make great software engineers :P

0celouvsky

3:52 AM

they're trying to harness the force in the extra dimensions for something

loltospoon

Yea Google is a broad tech company and FB is becoming one too

Amazon has drones now

Anonymous

SpaceX might have some offers, perhaps

loltospoon

I just want to build cool tech

SpaceX yea

Anonymous

@loltospoon Do you have any practical/experimental experience? In building stuff? In physics undergrad you mostly learn theory...

Anonymous

@loltospoon Well, you should have taken up engineering then :-P

loltospoon

3:55 AM

@blue yea....mostly theory haha. I plan on doing some research either this summer or in the fall

Also, true. I didn't have much guidance growing up, so yes this was a mistake but oh well, I'm gonna run with it and make the best of it.

Anonymous

BTW I think you should get a higher degree in engineering or physics...before getting into jobs....experience matters a lot...and the field is too competitive....

loltospoon

But I've always liked math/science/tech, so it wasn't a YUGE mistake...

Anonymous

In India atleast, physics undergrads hardly get any jobs...other than teaching and stuff....

loltospoon

Well I'd be applying to places in the U.S. haha...

Anonymous

@loltospoon You have a LOT of time! :-)

Anonymous

3:58 AM

I guess I'll chicken out...I don't think I am experienced enough too comment on your situation

Anonymous

:-P

Anonymous

All the best for your endeavors :-)

0celouvsky

@SirCumference I am reading a book on heat flow and am really liking it

it put me in a good mood

Sir Cumference

That's good

Sounds like a hot topic

...ok

Anonymous

@0celouvsky thermo ? which book?

Slereah

4:02 AM

hey hey

Sir Cumference

howdy howdy

0celouvsky

@blue pages.uoregon.edu/gilkey/dirPDF/InvarianceTheory1Ed.pdf

Anonymous

I've never found a good book on thermodynamics :-P

0celouvsky

it's not thermodynamic heat

pseudodifferential heat

@Slereah sleep better today?

Slereah

yeah

as u may notice

It's 6 AM in the real workd

Anonymous

4:04 AM

@0celouvsky Oh, I was looking for a good thermodynamics book :-P

0celouvsky

@Slereah did you know there's a proof of the Atiyah-Singer theorem using a supersymmetric path integral

I never understood how that worked

loltospoon

its ok, thanks for your help @blue

0celouvsky

I also now know how to take the trace of $e^{-tP}$, where $P$ is an elliptic operator

quite pleased

Slereah

@0celouvsky Well, odds are good that I would have seen it had I done my thesis

v. sad

0celouvsky

maybe I can do thermal field theory

Slereah

4:06 AM

do u want to do my thesis topic for your thesis

I still have it somewhere

0celouvsky

idk, but I expect SUSY will pop up somewhere

I bet yours involved algebraic geometry

f that

er mah gerd $\mathrm{Tr}\,e^{-t\Delta}$

this really is stat mech

Slereah

dropbox.com/s/pnallt6quyhcw4q/…

that's the one

0celouvsky

um

who is M. Lereah?

Slereah

it me

0celouvsky

your name is not M.

Slereah

4:10 AM

M. is Mister

0celouvsky

does it mean Mr.

Slereah

yes

Monsieur, if you will

"In particular, an alternative physical proof of the Atiah-Singer theorem (that theorem counts the number of zero modes of the Dirac operator on an arbitrary manifold) was constructed [2]"

0celouvsky

I need Steenrod.

@Slereah Yup, that

Slereah

Ahah

He said that an even clearer proof was made

and then he references himself

Although the paper also includes Ivanov

I think that was his previous student

0celouvsky

"proof"

Slereah

4:12 AM

arxiv.org/abs/1012.2069

0celouvsky

u could be doing that

Slereah

that has passed

0celouvsky

y tho

Slereah

I wonder if he ever found someone to do it

Or if the financing people shafted him because he wasn't doing standard model stuff

0celouvsky

so what's this web development thingie about

Slereah

4:21 AM

Learning the mysteries of the web

Basically learning php, html, css, javascript and sql

The five devils

0celouvsky

I see

sounds fun

Slereah

Well I need me money

got a house to buy

0celouvsky

that arrow is supposed to be a loop

can you do a line integral where the path goes out to infinity?

Slereah

yes

that's fairly common for contour integrals

I don't know how rigorous it is but it is certainly done

Yashas

qz.com/495098/…

0celouvsky

4:28 AM

I'm not exactly sure what that integral is supposed to do

I guess I will see later on

@Yashas sounds like a guide to pass JEE Advanced with ease

Yashas

I am going to try it in a mock test

Anonymous

Eh, please don't

Anonymous

You'll fail miserably

Anonymous

I tried it many times

Anonymous

Got negative marks instead :-P

Anonymous

4:30 AM

Guessing simply doesn't work when more than one option can be correct

Slereah

I used to find it weird that propagators and such had like those tiny imaginary parts to go under and over poles

But I think that's because they are distributions, and that kind of behaviour is well defined for those

0celouvsky

$$|D_x^\alpha D_\xi^\beta D_\lambda^\gamma q(x,\xi,\gamma)|\le C_{\alpha\beta\gamma}(1+|\xi|+|\lambda|^{1/d})^{k-|\beta|-d|\gamma|}$$

wtf

@Slereah it's all BS dude

Yashas

@blue Read that article.

Anonymous

@Yashas Read it

Yashas

@blue I am going to mark my confidence level on guesses next time

Anonymous

4:32 AM

bogus

0celouvsky

the $i\epsilon$ stuff works magically

Yashas

@blue there is no harm in trying?

I have around 30 more mock tests to write

0celouvsky

THIRTY MORE

Anonymous

30???

Yashas

once I tell my friends too, they are going to try it as well

Anonymous

4:33 AM

You're mad

Slereah

@0celouvsky I think it's possible to define rigorously but then you have to define them as distributions

Yashas

there are 40 days more

one everyday

0celouvsky

lol

wtf

Yashas

wot?

Anonymous

Marks you get won't be proportional to number of tests you give :-P

Anonymous

4:33 AM

That is for sure

0celouvsky

@Slereah I do believe the procedure involves switching limit and integral so you have to be really, really careful

Yashas

@blue I have nothing else to do

0celouvsky

You might get some wk* convergence in $\mathscr D'$

Yashas

Only revision and mock tests

0celouvsky

I'm not sure

Anonymous

4:34 AM

@Yashas Go and study :-P

Anonymous

The syllabus is huge

0celouvsky

@Yashas you have a gf?

Yashas

mock tests indicate what I need to focus on

Anonymous

And you suck at inorganic :-P

Slereah

Yeah I'm not sure of the exact process

Yashas

4:34 AM

@0celouvsky I have never had one :d

Anonymous

@0celouvsky Naaaaa

Yashas

becaz I am asexual

Anonymous

JEE people are saints

Slereah

I'd have to read those big papers on Wightman QFT or something

0celouvsky

haha

Slereah

4:34 AM

But I'm back to GR baby

0celouvsky

asexual is code for zero game

Anonymous

They give up on everything

Slereah

GR is great

Anonymous

Even food

Yashas

Ohhh but there are few girls who take those 30 mock tests too

0celouvsky

4:35 AM

@Slereah I can send you Coulombou for $30

Slereah

Structuring a GR book is pretty shit because I have no idea of where to put anything

Anonymous

Well hardly any girl qualifies advanced

Anonymous

I'm being sexist here

Anonymous

:-P

Slereah

Colombeau*

Anonymous

4:35 AM

But that's true

0celouvsky

triggered

Yashas

becaz girls have a weaker right brain

0celouvsky

@Slereah whatever

Yashas

idk where I read it

but they have a better left brain?

0celouvsky

that sweeping generalization tho

Anonymous

4:36 AM

@Yashas hush, you will never get a girlfriend

Yashas

:D

Slereah

unless you mean that guy

Columbo getting angry

►

Anonymous

well I think girls are more skewed towards arts subjects

Yashas

They are more of a problem than good

0celouvsky

I need to watch that show

Anonymous

4:37 AM

rather than science subjects

Slereah

I do love Columbo

Anonymous

but i wouldn't say they have weaker brains

Anonymous

lol

Slereah

There's plenty of girls in science but they're usually in biology

Or the """social sciences"""

Yashas

^^^^

0celouvsky

4:37 AM

what is spock doing there?

Anonymous

boys have very low eq (in general)

Slereah

Spock did a crime

Yashas

what's EQ?

emotional quotient?

Slereah

emotional quotient

Yashas

2 mins ago, by Yashas

but they have a better left brain?

Anonymous

4:38 AM

psychologytoday.com/blog/the-scientific-fundamentalist/201010/…

Anonymous

@Slereah Right

Yashas

:|

0celouvsky

I've noticed many JEE people come through here that are very strange towards women

Not really sexist, just don't care

Not normal for teenage boys

Yashas

mby all JEE toppers are asexuals :O

Anonymous

@0celouvsky I told you na, we give up everything :-P

Anonymous

4:40 AM

even food and sleep

Anonymous

lol

0celouvsky

Maybe JEE is a castration scheme for nerds

Yashas

as asexuals have less to worry about, they are more intelligent :D

Anonymous

Yeah, we become asexual

Anonymous

:-P

Yashas

4:40 AM

u asexual too?

why do I see a pattern now?

Anonymous

Almost everyone who qualifies jee advanced has to become asexual

Anonymous

lol

Yashas

Now I really want to get some stats and count how many asexuals are there in top 1000 ranks

-_-

Sexuality gets decided when the person is inside the womb?

Anonymous

but later they become desperate in college when they don't find girlfriends in college :-P

Yashas

Prenatal hormones and sexual orientation

The hormonal theory of sexuality holds that, just as exposure to certain hormones plays a role in fetal sex differentiation, such exposure also influences the sexual orientation that emerges later in the adult. Prenatal hormones may be seen as the primary determinant of adult sexual orientation, or a co-factor with genes, biological factors and/or environmental and social conditions. == Sex-typed behavior == The hormonal theory of sexuality and gender identity holds that, just as exposure to certain hormones plays a role in fetal sex differentiation, such exposure also influences the sexu...

Anonymous

4:42 AM

same old iit story

0celouvsky

is IIT full of desperate males?

Sir Cumference

Kind of envy asexuals...

0celouvsky

oh my god

Yashas

@0celouvsky maybe

Anonymous

@0celouvsky Well, 80 percent, yes :-P

Yashas

4:43 AM

becaz the sex ratio is like 100 males per 5 females

0celouvsky

lol

Anonymous

Girls don't qualify the exam

0celouvsky

like any of those guys could get girls anyway

Anonymous

Well, 20:1 boys to girls ratio

Anonymous

IIT girls are lucky

Yashas

4:44 AM

low with a ratio of 1:150 in mechanical and civil branch

0celouvsky

100:5 is 20:1

Yashas

omg

1:150 LOL

Anonymous

They get hit on by everybody

Anonymous

hehe

Anonymous

@Yashas haha

Anonymous

4:45 AM

I'll pick up girls from other colleges nearby...not to worry

Anonymous

:-D

Yashas

Aw, you are going to making the boys from that college jelly.

might start a local civil war

(you know; men are stupid)

no wonder why missiles are shaped like d***

Anonymous

@Yashas Yeah, they'll be jealous...coz I'm so hot ;)

0celouvsky

wtf

missiles are shaped aerodynamically

what are you on about

Yashas

I threw that statement in without providing any context lol

Anonymous

4:47 AM

I bet the same situation occurs in MIT

Slereah

Well

Yashas

Nope

MIT has a sex ratio of 1:1

Anonymous

Doesn't it ?

Sir Cumference

Anyone wanna help me with JS?

Yashas

becaz it is not a exam which decides admissions into MIT

0celouvsky

4:47 AM

MIT aggressively recruits girls

Slereah

Missiles and dicks have similar shapes due to similar requirements

They both have to reduce fluid friction

0celouvsky

^ban

Anonymous

MIT admissions are worse

Yashas

no they are better

but bad

Anonymous

no logic at all

Yashas

4:48 AM

IIT admissions are stupid

IITs reject international olympiad medalists, owners of startups, etc.

Those people are taken by MIT, Harvard, etc.

and they do something big

then the Indians will complain THEY LEFT THE COUNTRY; BETRAYERS!

Slereah

also same reason swords have that shape

Anonymous

MIT rejects olympiad medalists also....

Yashas

and then the student will answer "you sent me out of the country"

Anonymous

even they reject full marks in SAT guys

Yashas

@blue becaz they take people who are not robots

but they take IITJEE rank 1s though

Anonymous

4:49 AM

And reject rank 2

Anonymous

lol

Yashas

1 out of every 5 Indian gets 800 in Math lol

SAT is our 10th grade syllabus

it is funny

0celouvsky

oh not this again

Yashas

our 10th grade is their 12th grade lol

Anonymous

Whatever, I am not fond of the US Ivy admissions

Anonymous

4:50 AM

They are very uncertain

Yashas

they so called AP is our regular high school syllabus

Anonymous

@Yashas Stop boasting about India now:-P

Yashas

I am not :|

0celouvsky

@Yashas maybe you should take your tests so you don't fail

Anonymous

^^^

Yashas

4:51 AM

MIT has also rejected a student who made a nuclear reactor in his home

Anonymous

30 tests

Yashas

I don't have one today

0celouvsky

you're clearly not that smart if you have to take 30 tests

so maybe stop bashing America and go take tests

Anonymous

Ah, don't fight now

Anonymous

:-P

Slereah

4:55 AM

windows 7 has no option for mono sound

what is this madness

Fawad

> Stretched strings,coiled springs ,air,etc., Are examples of elastic media

What is elastic media?

Slereah

"media" is plural

so what are elastic media

Fawad

Of "medium" so statement has typo?

@Slereah yes

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