The h Bar

12:46 AM

@SirCumference Keep in mind that there is no reason to think that space is granular merely because there is a limit to the precision of measurement. There is nothing preventing you for learning that two objects are 1.3 or 1.4 plank lengths apart, just from learning that they are separated by 0.9 plank lengths.

0celo7

It is done

5 pages

dropbox.com/home?preview=m447+study+guide.pdf

the midterm review for calculus is done

user218912

1:31 AM

@0celo7 that's not the share link.

0celo7

it's not?

what is it

user218912

it brings me to my dropbox.

0celo7

porn?

dropbox.com/s/wxfvpiz9383bj22/m447%20study%20guide.pdf?dl=0

try that?

user218912

yes

user218912

looks dense

user218912

1:33 AM

I used to type notes like that, or even more dense, but then I realized it's difficult to study off of.

user218912

it's so much easier to study from if you bold specific terms and put spaces between each new theorem or statement.

0celo7

I didn't use it to study

user218912

then what is it for?

0celo7

I read my notes, when I understood the proof, I wrote the result on there

it's a checklist

user218912

oh

user218912

1:36 AM

btw I didn't forget the book.

user218912

just been broke lately

user218912

since 70 usd is like $100 for me.

0celo7

I don't need the book

If you want to get it, ok, but I'm not expecting it

user218912

which book do you need then?

user218912

preferably 70 or under.

0celo7

1:44 AM

I don't need any books

Bernard Meurer

@0celo7 Where your notes at boi?

user218912

@0celo7 yes I do want to get it because I said I owe you and I will buy it soon.

user218912

but if you don't want lee, then which other book?

Sir Cumference

All right, I need help.

Say we've got a black hole that releases Hawking radiation and thus is not eternal. As we approach the black hole, time dilation would increase between me and the rest of the Universe.

Before I reached the event horizon, would the black hole have already evaporated?

@0celo7 You know GR, right?

Could you answer that?

0celo7

@BernardMeurer the link is literally right above.

Bernard Meurer

1:58 AM

@0celo7 Those aren't good though :/

It's just a bunch of definitions clumped together

Sir Cumference

Goddammit, where's CW when we need him...

He was the most familiar with GR out of all of us here

0celo7

with this GR yes

Bernard Meurer

@SirCumference He is forever gone

Sadly

Sir Cumference

@BernardMeurer I know :'(

0celo7

he didn't know Lorentzian geometry though

Bernard Meurer

2:00 AM

@ChrisWhite we deeply miss you

0celo7

@obe Intro to the h-Principle, A Course in Minimal Surfaces.

But I could benefit most from Lee.

Oh and that expensive ass GR book. There are two expensive ass mathematical GR books I could use.

@BernardMeurer and theorems!

Do you want me to write a book on analysis?

Bernard Meurer

@0celo7 Well, some explanation would be good

You always give me shit for just writing maths klingon

I don't see why you get a pass

0celo7

because this is a study guide

Bernard Meurer

Some explanation would be good

better formatting too

but you seem to be on the right path

0celo7

what's wrong with the formatting?

@BernardMeurer dude give me hard problems from your homework

I need to practice.

Bernard Meurer

2:04 AM

@0celo7 I could translate the problems from my analysis book

Some are nice

0celo7

go for it

Bernard Meurer

Will do

but we have to use GitHub

0celo7

dude I have an exam in like 10 hours

I'm not learning to use that now

Bernard Meurer

Not now, I mean throughout the week

0celo7

well I have to practice NAO

Bernard Meurer

2:09 AM

Which subject?

0celo7

analysis

Bernard Meurer

What in analysis?

0celo7

uhhh

derivatives

I'm weakest on those

Bernard Meurer

Okay, sec

user218912

@0celo7 is that supposed to be a pun?

0celo7

2:15 AM

no, why would it be a pun?

user218912

weak derivative is a thing.

0celo7

didn't know that

what is it?

user218912

idk analysis

user218912

i just read about it

user218912

i'm 100% sure you know exactly what it is

0celo7

2:17 AM

...maybe I do

user218912

xD

Bernard Meurer

Let $I\subset \mathbb R$ an open interval, $J$ a limited interval contained in $I$, and $F_n$ a sequence of differentiable functions in $I$. For each $n\in \mathbb N_1$ and each $x\in I$, $f_n(x)=F'_n(x)$, admit that the sequence $f_n$ converges uniformly on the interval $J$ for the function $f$ and also that, for some point $c\in J$, the sequence $F_n(c)$ is convergent.

0celo7

limited interval?

Bernard Meurer

In these conditions prove that the sequence $F_n$ converges uniformly in $J$ to a function $F$, differentiable inside the interval $J$ and, in each point $x\in \text{int } J$, the equality $F'(x)=f(x)$ is true

@0celo7 It's what it says here

Sir Cumference

@BernardMeurer How'd you write the set of all natural numbers?

0celo7

2:23 AM

ok this problem is nontrivial.

give me a minute

Bernard Meurer

@SirCumference $\mathbb N$

Sir Cumference

@BernardMeurer K thx

$\mathbb N$

@MAFIA36790 Howdy

0celo7

ok

Each $f_n$ is differentiable, right?

wait

what kind of shit notation is this

Oh, ok. So $F_n$ are differentiable

@BernardMeurer Trivial.

user116211

@SirCumference Hey

0celo7

Clearly each $f_n$ is integrable. So $F_n(x)=F_n(x_0)+\int_{x_0}^x f_n$, where $x_0\in I$

Write $F(x_0)=\lim F_n(x_0)$.

Since $f_n\rightrightarrows f$ on $J$, $f$ is integrable and $\lim \int_{x_0}^x f_n=\int_{x_0}^x f$.

So we can take the limit of the first equation, and get $\lim F_n(x)=\lim F_n(x_0)+\int_{x_0}^x f$.

My $x_0$ is your $c$

So we have $F(x):=\lim F_n(x)=F(x_0)+\int_{x_0}^x f$.

Hmm, after that things get harder :P

It's clearly differentiable with the correct derivative.

Uniform convergence is harder.

Oh no, use the mean value theorem for integrals.

@BernardMeurer Ok, next

Bernard Meurer

2:35 AM

The proof here is 2 pages long dawg

0celo7

Not using integrals I assume

Nope

they use integrals?

No

ok

next problem

Sir Cumference

3:16 AM

Is Most Published Research Wrong?

►

This is kinda scary

It means we can misidentify particles

user218912

@SirCumference how far did you get in the notes?

Sir Cumference

@obe Still on page 63

Been focusing hard on school

user218912

not bad.

user116211

3:36 AM

13

Q: Can an irreducible representation have a zero character?

I asked the following question on Stackexchange, http://math.stackexchange.com/questions/1978407/can-an-irreducible-representation-have-a-zero-character but it got no answer, so I ask it here. Is there an example of the following situation : $F$ is a field, $G$ is a finite group, $\rho$ is an ...

Sir Cumference

3:47 AM

@obe Are you planning on posting more answers?

Reach the > 200 rep club

darn it bl00beLord

user228700

Anybody doing Chemistry here? (Pls 🙏)

Sir Cumference

@Kaumudi Just ask

user228700

There is no point in just asking if nobody knows. I've already asked at the CSE chat.

Anonymous

ask me

Anonymous

@Kaumudi

Anonymous

4:00 AM

tell the question

user228700

OK! Here:

user228700

in The Periodic Table, 11 mins ago, by Kaumudi

I've been trying to figure out the hybridization of the oxygen atom in furan. Since there are two lone pairs and it is bonded to tao carbon atoms, the steric number comes out to be 4, hence $sp^3$, yeah?

user228700

in The Periodic Table, 11 mins ago, by Kaumudi

Apparently, it's actually $sp^2$. How come?

Sir Cumference

@Kaumudi "CSE"?

0celo7

chemistry stack

Sir Cumference

4:03 AM

Oh, you meant "C SE"

user228700

So I read that I musn't include both lone pairs whilst calculating the steric number of oxygen, since one of these is actually delocalized throughout the molecule due to resonance.

user228700

@SirCumference Yep.

Anonymous

dont call me sir..i'm of your age only...btw furan is aromatic...so it must be sp2

Anonymous

2 bond pairs + 1 lone pair

user228700

But how am I to figure to out which electron pairs are delocalized and which aren't?

user228700

4:04 AM

@S007 When did I call u sir..?

0celo7

^

Anonymous

you know huckel's rule?

Anonymous

SirCumference

Anonymous

sorry

Anonymous

misread

Anonymous

4:05 AM

you know 4n+2 rule?

user228700

@S007 Yeah, I started out, trying to figure out if furan is aromatic or not, using Hückel's rule.

Anonymous

hmm so

Anonymous

one lone pair is delocalized

Anonymous

take 2+1 =3 i.e sp2

Anonymous

forget the other lone pair

user228700

4:06 AM

Yes, how to know if it is delocalized in the first place? (W/o already knowing that furan is aromatic)

Anonymous

W/o already knowing that furan is aromatic---- you can't

Anonymous

you must know it is aromatic

user228700

That can't be true :/

Anonymous

why?

user228700

What if u're trying to figure out if it's aromatic or not?

Anonymous

4:08 AM

then use huckel rule

user228700

Okay, how would u do that?

user228700

How many $\pi$ electrons are present?

Anonymous

see if lone pairs are present...then a cyclic ring always tries to gain aromaticity

Anonymous

so it takes only 1 pair of electron

Anonymous

from O

Anonymous

4:10 AM

and leaves the other one localized

user228700

Huh?

user228700

I don't understand the steps that u are following to arrive at the fact "and leaves the other one localized"

user228700

Also, can u direct me to a source that says that "if lone pairs are present, then a cyclic ring always tries to gain aromaticity"?

Anonymous

aromticity=stability

Anonymous

I cant find a source now

user228700

4:12 AM

OK..?

Anonymous

*aromaticity

user228700

Can u pls elaborate?

Anonymous

on what?

Anonymous

read wiki en.wikipedia.org/wiki/Furan

user228700

How did u determine that one lone pair is delocalized?!

Anonymous

4:14 AM

2 pi bonds have 4 e

user228700

And as for Hückel's rule, well, u couldn't possibly have used it w/o knowing that one lp is delocalized!

Anonymous

and 1 more lp needed to make it 6 e

Anonymous

to make it aromatic

user228700

Aaah! But this is under the assumption that furan is already aromatic!

Anonymous

no

user228700

4:15 AM

When using Hückel's rule, we generally don't know if the compound is aromatic or not.

Anonymous

every ring tries to be aromatic

user228700

U said "to make it aromatic", which implied that u already knew that furan is aromatic!

Anonymous

so even if 8 electrons are present

user228700

What if it wasn't and u did this, to find that it is somehow aromatic. Ur answer would be wrong!

Anonymous

it must be aromatic

Anonymous

4:16 AM

because there are 8 total pi electrons

Anonymous

initially

Anonymous

but i reject one

Anonymous

to make it aromatic

user228700

Yes, how did u reject one pair?

Anonymous

to satisfy huckel

Anonymous

4:17 AM

by force

user228700

>To make it aromatic

user228700

That's not how it works, dude.

user228700

chem.libretexts.org/Core/Organic_Chemistry/Hydrocarbons/Arenes/…

user228700

Read that ^

Anonymous

"That's not how it works, dude." ----well if you think you know better you should not be asking here

Anonymous

4:18 AM

bbye

dm__

quick GRE problem question, causing intuitive confusion. anyone willing to provide a different perspective?

anyone here?

user116211

@dm__, ask your question. If someone is interested, he/she would respond.

user228700

@S007 Whilst I'm still not very clear on how it works, I can definitely ascertain that ur line of reasoning will lead to wrong answers. I'm not trying to be condescending or anything. It's called a discussion; we are helping each other.

Anonymous

Show me one example where my method doesnt work

Anonymous

Then I'll accept.

dm__

4:26 AM

cool. oil sits on top of water. a block is immersed, floating in the boundary between the two. now, how in the world does the oil, which is on top, supply an UPWARD buoyant force? the sides and top of the block contact oil; side pressures cancel, and wouldn't the top pressure be down?

user228700

I've only just started working with this and exceptions pop out from places u'd never expect to find them. I agree that rings want to be more stable and that if they can help it, they will be aromatic but I'm saying that we shouldn't force Hückel's rule on the compound. Ur method may give u the correct answer but the conceptual understanding behind that method might not be so clear.

dm__

it is #31 on this: ets.org/s/gre/pdf/practice_book_physics.pdf

Anonymous

@Kaumudi every compound wants stability...that is the conceptual reason

Anonymous

we always force huckel's rule whenever possible

user228700

Sigh. Alright, I dunno man, I might be wrong too. I just feel that "forcing Hückel's rule" might not be the best way to do it and also, it is not something I've read anywhere.

user228700

4:29 AM

Here, I found this and this cleared my doubts:

Anonymous

you will not find it in standard texbooks

user228700

google.co.in/url?sa=t&source=web&rct=j&url=http://…

Anonymous

ask your teacher

rob

@dm__ Suppose that the block, which floats in water, were resting on the bottom of an unfilled container. Water is poured in and occupies only the sides and top of the block. Doesn't your argument suggest the block should not float?

dm__

nice! ok, how is that resolved?

rob

4:30 AM

@dm__ The oil is also exerting pressure on the water, and via the water to the bottom of the block.

user228700

@S007 Exactly the problem. Teachers often tend to make these little tricks to do the problems in exams but I'm just saying that it might not always work! Again, I might be wrong. Anyway, I've found my answer. Thanks.

dm__

woah, right on. thanks!

Anonymous

these are not tricks...this is pure logic

Anonymous

think from a molecule's point of view

rob

@dm__ no problem.

Anonymous

4:32 AM

anyway you are welcome

Anonymous

goodbye

user228700

@S007 Yes, it does make sense. The molecule wants to attain stability but aah, I dunno man, tell me if u find an exception. Bye.

Anonymous

I never found an exception out of the 100s of problems i solved

Anonymous

:-)

dm__

@rob what about the one you posed? if the block is sitting at the bottom of the container, FLUSH with the surface for sake of argument, wouldn't it remain at the bottom?

Anonymous

4:33 AM

tata

dm__

when water is poured in

rob

@dm__ that's called a suction cup.

dm__

sweet

Sir Cumference

My parents are pissed that I have a "micky-mouse" major

rob

@SirCumference Don't be ashamed. Animation is big business.

user116211

4:35 AM

@SirCumference WTF ;/

Sir Cumference

Is there any paying job where you use your mind?

Wow...screwed that up

user116211

@SirCumference yes.

Sir Cumference

But yeah, I'd like a paying job that makes me use my brain. And preferably numbers.

user116211

See if your university department has any undergrad research programme.

Sir Cumference

Research is out.

user116211

4:36 AM

._.

Sir Cumference

@MAFIA36790 Researchers don't make much...

Especially with all the studying they have to do beforehand

Most people become astronomers at 35

user116211

Then join a casino.

Sir Cumference

...

Sigh...

There's no paying job that makes me use my brain...that's really depressing

Not enough people see the beauty in math.

dm__

ma(beauty)th

found it!

Sir Cumference

At this rate, the kids in the back of my old high school math classes yelling "When are we ever going to use this?!" will be right...

rob

4:39 AM

@SirCumference I don't agree with you here for the case of funded graduate students.

Sir Cumference

@rob My point there is that the amount of studying beforehand produces a mediocre salary, in too many cases

dm__

money does not matter.

user116211

It matters.

rob

@SirCumference I won't deny that a graduate student stipend is mediocre for a full-time job.

Sir Cumference

@dm__ It matters

You need to put food on the table

dm__

4:41 AM

not a lot of money needed to do that

Sir Cumference

Don't be idealistic

dm__

don't be greedy

rob

But, I was able to start my family during grad school.

Sir Cumference

It's not greed

user116211

@rob WOOW!!!

Sir Cumference

4:42 AM

It's worry that I might not be able to support a family

user116211

I can't support my dog, let alone myself.

Sir Cumference

@dm__ If money isn't the problem, finding a job is

There's not nearly enough jobs for researchers

user116211

Sell weeds.

Sir Cumference

I'd rather not put all my work into one dream only to find myself unemployed years later

user116211

You will be millionaire.

Sir Cumference

4:43 AM

That's a scary thought

rob

@SirCumference What are you studying?

Sir Cumference

@rob Astronomy

dm__

a thought, that's all. don't attach to the future

Sir Cumference

@dm__ There's too many cases of that

dm__

don't be a case

you are you

Sir Cumference

4:44 AM

This doesn't sound like planning for the future...

rob

@SirCumference Yes, astronomy is pretty competitive, especially at the permanent-position level.

Sir Cumference

@rob Not to mention, it requires more than 15 years of studying after high school, plus it doesn't pay well...

dm__

only way to find out is to venture into the great unknown! the place that plans go to die

rob

@SirCumference Fifteen years sounds like an overestimate.

Sir Cumference

@dm__ I'd rather not spend my whole life working hard, only to find myself unemployed and unable to support myself or a family

user228700

4:46 AM

@S007 OK. Ur conceptual understanding is sound. Maybe I just didn't understand it the first time u explained; I'm sorry.

Sir Cumference

That's too great a risk.

@rob That's what a few astronomers told me

Even my professor said 13+ years

Anonymous

@Kaumudi Now are you confident about aromaticity?

rob

@SirCumference Where are you in the curriculum now?

Anonymous

Good !

Sir Cumference

@rob I'm still a freshman, only a month into my courses

Well, almost 2

user116211

4:47 AM

@SirCumference Well, me too.

user116211

But I have not pondered so much far about the future.

Sir Cumference

We're going over hydrostatic equilibrium formulae and such

@MAFIA36790 Well, my parents are calling me and they're pissed

rob

@SirCumference So, no matter what, you're going to get some sort of undergrad degree. That's four years.

user116211

@SirCumference ohh.

Sir Cumference

Sigh...this is too stressful...

@rob I've done the math, it seems like less than 15, but that's what the people told me...

user116211

4:49 AM

Join some gang in Mexico; or join a casino; or start a business.

dm__

it's stressful because these are artificial. you are compressing 15 years of your life into a few sentences. it is not helpful

Sir Cumference

@dm__ If you don't mind me asking, how old are you?

rob

For an astronomy major, you're going to cover a lot of the same material as a physics major: strong mathematical background, classical mechanics, complex problem-solving skills, computer programming.

user228700

@S007 Yes :-) BTW, "100s of problems" wtf?

user116211

I have wondered @rob, why you people have 4 yrs of undergrad degree; we have only 3.

rob

4:51 AM

When you get your undergrad degree, that's a decision point. You can continue at that point. Or, you can get out and become an actuary or something.

Sir Cumference

@rob Isn't that a bit late?

user116211

@SirCumference NOO!

Anonymous

@Kaumudi Well preparing for jee...so :-P

rob

Insurance companies and actuarial firms love science majors, and pay well, and ... offer great insurance

user228700

@S007 Oh :-P U're in grade 12/11?

user116211

4:51 AM

Hey @S007, Indian!

Sir Cumference

@rob I've brought up employability in the past, here....

rob

@MAFIA36790 "We" == Europe? England?

Sir Cumference

@dmckee woke me up about that

user116211

yes.

Anonymous

@Kaumudi 12

Anonymous

4:52 AM

you?

user228700

Ah, OK. I'm a dropper.

Anonymous

@MAFIA36790 hi :-)

Anonymous

@Kaumudi all the best

Anonymous

lets study now

Anonymous

tata

rob

4:53 AM

@SirCumference This is true, but it's true to some extent for every major.

Sir Cumference

@rob Well, I'm not sure when it'll be too late to decide

I know even less what I want to go into. Preferably something payable and with a good amount of jobs, but also requiring me to use my brain...

rob

@SirCumference You're a freshman. Do things that you enjoy. Do them well and make connections. Ask your connections for advice that's tailored to their experience and your experience.

5

user116211

I have seen many people changing their fields after their Bachelors; so it's not a problem @SirC.

user116211

Even people of physics go to maths after their graduation or vice versa.

rob

Consider the number of people who get undergrad degrees in history and literature, then leave those fields.

dm__

4:57 AM

@SirCumference and give your mind a break, drop the future for a while

rob

You'll be just as prepared for a general "job market" as those folks are.