The h Bar

Avantgarde

18:00

Oh Bowie, ok. You probably did share this. Let me see..

yeah you did. I listened to some of it

I do like whatever Bowie I've heard. Not a lot though.

Balarka Sen

what do you think of it

Avantgarde

pretty good that he did this experimental work back in the day. It takes courage. And it's good too

Balarka Sen

It is the first of his Berlin trilogy, done with collaboration with Eno

Secret

in Mathematics, 2 mins ago, by Akiva Weinberger

@BalarkaSen "Can we interpret the universe in such a way that there's only one electron"

[Slereah Bomb]

Avantgarde

Sen just did a Wheeler

hm, let me look up some old prog rock..

Balarka Sen

18:05

Link me!

Avantgarde

It's been a long time since I last listened to them, so I can't really recommend a 'good' song, but it was a good band. Here's one of the first few songs on youtube

Caravan In the Land of Grey and Pink

►

If you like this sound, then you should look up 'Canterbury Scene'. A lot of prog rock bands from there came up around the same time. Like Caravan, Soft Machine, National Health etc.

Canterbury scene

The Canterbury scene (or Canterbury Sound) is a subgenre of, or sibling to, progressive rock. The term describes a loosely defined style of music created by a number of improvisational musicians, some of whom were based in the city of Canterbury, Kent, England during the late 1960s and early 1970s. These musicians played together in numerous bands, with ever-changing and overlapping personnel, creating some similarities in their musical output. Many prominent British avant-garde or fusion musicians began their career in Canterbury bands, including Hugh Hopper, Steve Hillage, Dave Stewart (t...

Soft Machine was a bit too bland for my taste. But if you like bland/weird old prog rock, then you will like it.

0celouvskyopoulo7

@BalarkaSen you into gangster rap now?

Balarka Sen

@Avantgarde Does Soft Machine have anything to do with The Soft Machine, a novel of Bill Burroughs?

Avantgarde

@BalarkaSen I have no idea

Balarka Sen

@0celo I was recommended it

i can not speak english

@Avantgarde Give me a moment; I'll finish some schoolwork in a moment and plug in headphones to listen to that thing

Avantgarde

18:13

@BalarkaSen Ok

AHB

About what do you guys talk here? anything?

Avantgarde

Yeah

Welcome

AHB

Oh.

Avantgarde

Are we?

0celouvskyopoulo7

Maybe

AHB

18:17

The description says "general chat".

So it actually is "general physics".

Shing

hey guys, I am confused about linear algebra: if a 5 x 5 matrix contain only all zeros in it. Is its column space still $R^5$?

0celouvskyopoulo7

it's the zero vector

David Z

@AHB Yes, anything. Though you should choose topics of discussion with a mind to what other people in the room are interested in.

Balarka Sen

Or the zero subspace, to be pedantic.

Shing

@0celouvskyopoulo7 oh I got it now. A zero vector with 5 components zero. Thanks!!

Avantgarde

18:20

Yes - Owner of a Lonely Heart

►

AHB

Does anyone here know about hermeneutics?

Avantgarde

Not me

0celouvskyopoulo7

yesterday, by SevenSidedDie

Here's a suggestion: talk about physics.

AHB

I am confused.

0celouvskyopoulo7

So am I

Avantgarde

18:22

About?

AHB

Someone said It can be anything. @David Z

Balarka Sen

Nothing at all

0celouvskyopoulo7

@Slereah Look, a (global) section $s$ of a vector bundle $V\to M$ is just an association of some element $s(x)$ of each $V_x$ for each $x\in M$.

Balarka Sen

It is a room both about everything and nothing. That means you can pretty much literally write whatever here, as long as it's written with responsibility.

0celouvskyopoulo7

@Slereah That's exactly what a vector field is.

Smoothness of a section is defined in terms of local frames.

David Z

18:24

@AHB Yes, I meant that we have no rules saying that particular topics of conversation are forbidden, nor saying that the room is limited to specific topics.

0celouvskyopoulo7

And for vector fields one can do the same thing.

AHB

OK @DavidZ

Avantgarde

@BalarkaSen Thanks for reminding me of Caravan. I'm revisiting and enjoying it after years!

Balarka Sen

Cool! I am done with my stuff now, about to get headphones

Slereah

@0celouvskyopoulo7 Smoothness on the bundle is gonna be the usual topological definition, though

While smoothness of a vector field will be mapping smooth functions to smooth functions

I'd like to show that the two are equivalent

AHB

18:30

I need some advice.

Avantgarde

Sure

AHB

About avoiding mistakes in solving problems.

Avantgarde

Which subject's problems?

AHB

specifically, problems of the physics Olympiad.

Avantgarde

Oh I can't say anything there

Shing

18:32

damn! I am confused again. Gilbert Strang's textbook is quite confusing sometimes

It says for a Echelon Matrice, even a component of every column is zero, for a (say, 4x7 matrix), the column space is $R^4$

AHB

The problem is that solutions are usually very long. with long formulas. You can easily forget a small "-" or "g", and finally the final answer may be even dimensionally wrong!

I think the level of problems are like that of first semester of university.

Avantgarde

Probably no. College level physics is different from the physics problems you get in olympiads.

Slereah

(also of course not all vector bundles are the tangent bundle so it can't simply be that we assign a vector to a point)

Shing

um... I think probably because the 7 column vectors are linear dependent...

0celouvskyopoulo7

@Slereah Here's the strategy.

Pick a coordinate neighborhood around $p\in M$. Let $x^i$ be a coordinate system, show that you can expand $X$ as $X=X^i\partial_i$, at least locally.

You now need to show that the $X^i$ are smooth. You can do this by acting on the coordinate functions. Then you get $Xx^j=X^j$. The LHS is smooth by assumption, so is the RHS.

Anonymous

18:40

@AHB What type of advice are you looking for?

0celouvskyopoulo7

The converse is similar.

So the two notions are identical.

Anonymous

@AHB There's nothing much you can do to avoid careless errors other than being careful and practicing.

AHB

avoiding mistake @Blue. When dealing with long calculations. I think it is something everywhere!

OK. what kind of practice? @Blue

Just blindly solve problems?

0celouvskyopoulo7

what calculations are you trying to do?

compute a few curvature tensors if you want a hard time

AHB

physics. mostly parametric ones.

@0celouvskyopoulo7 were you talking to me?

:)

Anonymous

18:43

@AHB You need to analyze the type of mistakes you make into three categories: 1) Conceptual Errors 2) Silly Errors 3) Conceptual Errors which you tend to call "Silly Errors".

AHB

Hmmm.

0celouvskyopoulo7

@AHB yes

AHB

The level is a little higher than highschool.

calculus, basic algebra, and hmmm.

physics!

0celouvskyopoulo7

how is that higher than high school?

that is high school

AHB

They take like 30 to 45 minutes one wverage.

I don't know about olympiad in other countries, but

0celouvskyopoulo7

18:46

oh no

another Indian doing some olympiad?

AHB

:/

Anonymous

@AHB Heh, if you are calculating the time you are taking to solve Olympiad problems then you are on the wrong path. Some problems might even take days.

Anonymous

@0celouvskyopoulo7 India is not the only country which participates in Olympiads.

AHB

"on average" I said.

0celouvskyopoulo7

@AHB Are you Indian?

Anonymous

18:47

@0celouvskyopoulo7 He is from Iran.

0celouvskyopoulo7

Same thing

Avantgarde

lol

AHB

and not my average! the problem designer has intended so.

Shing

Is Olympiad really sth worthy of it in the long run? I know it is very helpful for getting into a good undergrad, but how about conducting good research? (even to have a scientific mind)

AHB

Do you feel uncomfortable?

Shing

18:48

(I have no idea at all)

AHB

How about you ? @0celouvskyopoulo7

0celouvskyopoulo7

What?

Anonymous

@Shing Olympiad is not helpful if you want to go for research. But it definitely helps in developing a knack for problem solving.

AHB

@0celouvskyopoulo7 do you feel uncomfortable?

Shing

I see

Avantgarde

18:50

this is kind of a fun chat

0celouvskyopoulo7

@AHB What?

Anonymous

@AHB Free advice: Since you are a beginner, focus more on solving the problems(even if it takes days). The only way to get rid of silly errors on the D-day is to make as many silly errors as possible during your practice (while making an effort to minimize them).

AHB

@Shing I need the one year free time which is awarded if you get among the top ten of the country. I need that time for research ~.

Anonymous

@AHB Iran seems to have a competitive culture just like in all other Asian countries. :P Good luck!

Mostafa

@Shing I think it is a very good system for getting students interested in science. The emphasis shouldn't be on its competition aspect because, as I said yesterday about JEE, in such competetions only less than %1 can win.

AHB

18:53

@0celouvskyopoulo7 I though you don't like problem solvers from India.

Mostafa

Hi @AHB

AHB

Hi.

oh!

John Doe

If we consider a pure state $| \psi \rangle \langle \psi |$ and a the state $\hat{A}| \psi \rangle \langle \psi | \hat{A}^{\dagger}$, then can we always find a unitary operator such that $\hat{U}| \psi \rangle \langle \psi | \hat{U}^{\dagger} = \hat{A} | \psi \rangle \langle \psi | \hat{A}^{\dagger}$?

0celouvskyopoulo7

@AHB Problem solvers?

Strange way to describe it

AHB

ok. nevermind @0celouvskyopoulo7. that is ok.

0celouvskyopoulo7

18:55

I don't know what you are on about

AHB

@0celouvskyopoulo7 I failed to say what I meant, and It much wasn't important.

Anonymous

@Mostafa I agree with that. The aim should not be at winning the competition but learning as much as possible. Such competitions teach you a lot about working under pressure conditions. However, not getting into a good college doesn't mean one's life is wasted. Some of the top scientists and engineers in India had failed in JEE too. :)

0celouvskyopoulo7

Can we pleeeeeeease stop talking about JEE

AccidentalFourierTransform

J̨̡̢̥͓͇̮̦̯̰͕̲̺͇̟̜̞ͧ̐ͩͫ̽̿̇̊ͫ͢Ẽ̵̶̡̛͈̜͚̻͈̟̗ͯ̈͊͒̄Ȅ̷̡͕̪̺͚̼̪̰̝͙̝͈̬̂͗͐̉ͫ̈́̌ͭ̍̔̉̏̊͟Ę̴̸̛̻͕̱̥̖͈̫͙̗̺̖̦͈̟̬͉͚͙̣ͥ͂̾͒̃̑̇̕Ę̴̶̺̘̭͇̺̲͇̭̬̤̪̘͎͉̻͍̠̫̼̈́̀̄̔̀͌ͣ̓͌̂E̡̟͇̳̹̲̲̭̬͍̖̯̞̘̤̜̠͌̒̂̇ͪ̂̀̉ͭ͡ͅE͙̲̠̱̩̩̯̮̊̇̌ͯͧ̀͟Ěͣ͑ͨ̽ͯͯ̽ͣ̎̚͏͉̞̯͍̮̻̥̳͎̱̪̥̹̞͇̺̜͞Ȩ̯͖͇͖̼͙̜͙ͪ̎̌͑͌̏͒͝E̢̧͎̰̗̯̱ͨ̃́̌ͣ̓ͨ̿̉̊ͫ̉͋ͩ͆E̶͕̬̣̠̜̝̬̖̺̍̃̿̿̈́ͥ̾̎͌ͧ͘͢͜͞ͅ

AHB

I don't know what it is, but why is it that annoying? :)

0celouvskyopoulo7

18:58

People literally die because of it...

Anonymous

@AHB Long story. :P

AHB

@0celouvskyopoulo7 why same thing?

OH.

Avantgarde

That Sucks (CNN Remix)

►

Mithrandir24601

@AHB For comparison, first year undergrad questions took me a minimum of an hour each. As in, I was very happy with myself when I got a question done in an hour

AHB

how to reply to a specific message?

Avantgarde

19:01

Go to the message. Move to the extreme right. You'll see an arrow appear. That's the reply button

AHB

@Mithrandir24601 so they are like the final problems. they take an hour each.

Shing

I was told by a Nobel winner that "a bad school can't stop you from becoming a good physicist." but later I found what he didn't say is "a bad school is really a pain in the ass." ; however, then I learned that "shut up, and work the hell out of it" spirit. So, all in all, life will find its way out (I guess).

AHB

@Avantgarde Then I have done it right.

Avantgarde

@AHB Yes :)

Anonymous

@Shing That's really true.

Mithrandir24601

19:04

@AHB An hour minimum. It's hard to compare Olympiad questions with Uni questions - uni questions were harder, but then again we'd learnt more stuff, so if I went back to do Olympiad questions, I would have found them a lot easier because I had extra experience and more knowledge

AccidentalFourierTransform

in the Big Bang theory, when Rajesh talks with his parents

its funny because the three of them are from India

yet they speak in English

that is what sometimes the h-bar feels like :D

Shing

lol

Avantgarde

Some Indians speak English as their first language

Anonymous

@AHB I think Irodov's problems are a good start. I used to take atleast half an hour on each problem (while solving them the first time).

Mithrandir24601

@AccidentalFourierTransform I've had various friends that, when speaking to each other at various times, would either: 1. Speak in their own language; 2. Speak in English; and occasionally 3. change between their own language and English at various points

AHB

19:09

@Mithrandir24601 you are right. I haven't seen your problems. I think it won't be a good place to get advice either! Since, I will need to list what I have done and what I have read to make sure you get some idea about my knowledge.

AccidentalFourierTransform

yeah, some of you sometimes seem native English speakers to my (non-native) ears...

Mostafa

Random PhysSE sad fact #2: Although the answer I gave to this question is accurate, general and addresses the roots of the OP's problem, the other answer which arguably does none of the above and is even believed to be wrong by some experts has been accepted by the OP and even (sadly) upvoted by the community merely because it was posted sooner, and my answer has not received enough attention. Some pundits called this a political thing.

AHB

@Blue I didn't tell you where in the path I am. Yet you suggest books ass a good start?

John Doe

@Mithrandir24601 Hey how's it going?

Mithrandir24601

@AHB One thing I do remember is that the final bit we had in our practical bit (the bit that stumped me) was covered in the first week of lectures :/ So I could possibly be convinced that the Olympiad is a good bridge between what we have as A-levels and the undergrad

Anonymous

19:12

@AHB I just said about the path I followed.

Anonymous

You are free to neglect any advice not pertaining to your specific situation.

Mithrandir24601

@JohnDoe Hi - same old - still working on that essay... It's almost done - just one more subsubssection to go, so hopefully be finished tomorrow (although that's still probably a bit optimistic)

John Doe

@Mithrandir24601 You writing essays for your PhD?

Anonymous

@Mithrandir24601 That's primarily because we use English in our workplaces and schools and use our native language at home or informal gatherings. :P

Anonymous

English is the only language that is common to whole of India. Otherwise every state has a different native language.

AHB

19:15

@Blue Oh. so it was your own path. ok then... and, yes Irodov was good at the start. But I didn't like it much. thank you anyway.

Mithrandir24601

@JohnDoe I haven't started the PhD proper yet - this is what I can only think of as a 'learning year', so yeah... I've got one essay to write. I've also had 3 exams, 2 projects (only just started the second one) and a few other random bits and pieces

AHB

@Mithrandir24601 My mind can't process what you say. :-confused

Use simpler words. :]

John Doe

@Mithrandir24601 Sound like a lot work...

@Mithrandir24601 If you have a chance, have a look at this post. A measurement theory question.

Mithrandir24601

@AHB So essentially, we had pen-and-paper questions, followed by a practical. In the last bit of the practical, we had a thing (a certain type of a non straight-line graph) that I had no idea how to get the right answer out of. I then went to Uni and learnt about it within the first week. And so, it's entirely possible that the Olympiad is good preparation for Uni and covers the gap just before Uni

Anonymous

@Mostafa The problem is your answer might be too complicated for someone who has just started with ray optics. :P Explaining your equations from the scratch to a layman is a difficult task.

AHB

19:23

@Mithrandir24601 Yes. Oly is great.

Mithrandir24601

@JohnDoe Is the measurement operator in the same basis as the state and is this known?

AHB

Nice simpler-word translation btw :)

John Doe

@Mithrandir24601 This is not stated so I don't think we can assume that. All we know is that it is an efficient measurement and the initial state is pure.

Mithrandir24601

@AHB Thanks :) If you haven't heard of A-levels (don't know if this was causing confusion or not), that's the exams we do in order to get into Uni here (in the UK)

@JohnDoe What is an efficient measurement then?

Are we just performing a single 'one-shot' measurement, or do we have an ensemble?

AHB

@Mithrandir24601 Oh. We have an equivalent. called the konkour. The hurdle between you and "any" university in Iran.

Of course I mean the good ones...

Anonymous

19:29

@AHB A-levels aren't competitive exams like konkour though :P

John Doe

@Mithrandir24601 An efficient measurement is just a measurement that takes $\rho \to \frac{A_n \rho A_n^{\dagger}}{p_n}$. Just a single measurement.

AHB

So you have talked with Persians about educational system before ?

Anonymous

@AHB Yup

Mostafa

@Blue WHO

AHB

It wasn't you mostafa?

Mithrandir24601

19:32

@JohnDoe Are we including 'state collapse' in the measurement? Or are we just acting with the measurement operator to get a superposition of states in the measurement basis?

Mostafa

@AHB No I've never talked about Konkour here

Anonymous

@Mostafa Someone on Quora

John Doe

@Mithrandir24601 I think the latter.

Mithrandir24601

@JohnDoe AHH

The definition makes sense now :P

Mostafa

@AHB are you studying for the physics olympiad?

AHB

19:34

@Mostafa It has a wiki page btw en.wikipedia.org/wiki/Iranian_University_Entrance_Exam

Yeah.

Avantgarde

quora lost its shine

Just win baby

^

AHB

@Mostafa waiting for the results currently...

Anonymous

Quora is a good tool for procrastinating though XD

John Doe

@Mithrandir24601 So I think we need to define the unitary operator as a function of $m$ such that we get the final $\tilde{\rho}_m$ for each $m$. But I don't see an obvious way to define the unitary operator.

Avantgarde

19:35

You'll get bored of that too

Just win baby

Not as good as this place.

John Doe

@Mithrandir24601 Which is what I wrote...

Mostafa

@AHB Wish you luck! but don't really take this whole olympiad system too seriously (no matter you get the 1st gold medal, or nothing)...the learning part is much much more important than the medals.

It's just good for getting into the university you want easier

I mean, 5 years from now people will barely remember who was even studying for the olympiad..

AHB

@Mostafa Yes. I agree.

Mostafa

but the KNAWLEDGE , that's important, you know

Avantgarde

19:40

gnaw lej

AHB

Where do you study @Mostafa ? Your major is one of my favorites.

Mostafa

University of Tehran

AHB

And is that picture your real face?

nice.

Anonymous

lol ^ :P

AccidentalFourierTransform

lmao

AHB

19:43

It seems familiar to me...

Anonymous

rofl

Avantgarde

the real face of mostafa: chapter II

Bernardo Meurer

@Mostafa Hm? The Wiki page says nothing about Brazil

Mithrandir24601

@JohnDoe Well, a unitary is just a rotation of the state i.e. $\forall\left|\psi\right\rangle , \left|\psi '\right\rangle \exists U s.t. U\left|\psi'\right\rangle = \left|\psi\right\rangle$

(or at least, I'm reasonably sure that's right)

AccidentalFourierTransform

2

Avantgarde

19:45

lol

very nice

John Doe

@Mithrandir24601 I asked someone that a few minutes ago :) Might have been you?

Mithrandir24601

@JohnDoe I don't think so...

(and yes, what I wrote above is right)

John Doe

@Mithrandir24601 So then we can just define $U$ as the unitary operator which takes $| \psi \rangle$ to $A_m | \psi$?

Bernardo Meurer

@AccidentalFourierTransform Damn, how'd you get that

AccidentalFourierTransform

what

John Doe

19:48

@Mithrandir24601 I asked the room, no one replied... That would be convenient if that's all that has to be done.

Mostafa

What is the name of this effect: once a message is starred by someone, peopel are much more likely to rush and star that message

5

Mithrandir24601

@JohnDoe yeah, you can individually define each $U_m$ that maps $\left|\psi\right\rangle$ to $A_m\left|\psi\right\rangle$, or even the other way round if you want

AHB

@Blue What is funny?

Anonymous

@AHB Whatever is not non-funny.

John Doe

@Mithrandir24601 That's great. I suspected something not too complicated...Thanks.

Anonymous

19:50

@Mostafa I'd like to know the answer. :D

Avantgarde

John von mostafa

Mostafa

@Avantgarde lol

Mithrandir24601

@JohnDoe By the way, for me, it's really easy to think of this using the circuit model - every circuit is some unitary and you can reach any point on the Bloch sphere (and equivalent idea for $>1$ qubit) using some circuit etc.

Anonymous

Mostafa von Mostafa.

Mithrandir24601

@JohnDoe No problem!

(I just hope I'm not wrong now :P )

Avantgarde

19:53

@Mostafa maybe a case of en.wikipedia.org/wiki/Mere-exposure_effect

John Doe

20:08

@Mithrandir24601 Cool, I think it's right but will confirm it as well.

Anonymous

Hi @Sid

Avantgarde

super dead chat

Sid

~~morning~~ Hey!

Anonymous

Good night :D

Anonymous

Sup?

Anonymous

20:16

@Avantgarde You haven't seen real dead chats as yet then :P

Sid

I just reached home.

15 mins ago

Anonymous

@Sid Ho. From?

Avantgarde

I have! Music. Though after joining there a few days ago, it's gotten much beter

Sid

Had gone to school to collect my certificates

Anonymous

wtf...you went to school at midnight to collect certificates? :'D

Sid

20:18

Lol... No

Allow me to explain

Anonymous

People go to school at midnight to steal question papers though :'P

Balarka Sen

midnight is when the real shit begins yo

r/nocontext

Avantgarde

I remember cartoon network closing at 9PM and moving to showing old movies after that

Anonymous

Coldplay - Midnight

►

Sid

The school where I completed my 12th is 300 odd km away from home I.e. in another town. I lived there for 2 years alone for education. After exams, I had returned home. Yesterday, I got a message from school to come and collect the certificates. So, I caught a train today morning.

Anonymous

20:21

@Avantgarde On Hungama (after 10pm) they used to show ads like: "I used this device and my weight reduced from 100 kgs to 50 kgs in one week" XD

Avantgarde

@Blue lol, they probably still show that

those weight-reduction belts

Perturbator - "Retrogenesis" ["I Am the Night" - Remaster 2015]

►

Anonymous

@Sid Oh, I see. Better take rest now. :D

Sid

In the evening after my work was completed, I received a call from Dad that one of my relatives was in the same town as me and I should return with them. They started at 6:30PM. Took us 7 hours to reach home

Anonymous

@Sid Heh, so when school was on you used to travel 300km everyday? :O

Avantgarde

facepalm

Mostafa

20:24

Guess what ad I got when I opened that YouTube video?
Hint: [someone giving me nawledge](https://i.sstatic.net/8ckvb.png) abour how to invest in real estate

Sid

Nah. Lived alone in a rented house.

Anonymous

@Sid Oh

Avantgarde

lol

Anonymous

@Mostafa omfg...Tai Lopez XD

Sid

Either Mom or Dad would visit once a fortnight to see if I am alright.

Anonymous

20:26

I thought Youtube had blocked him

Mostafa

Why the link doesn't work :'(

Sid

Mom stayed during the entire 2-3 months of exams with me

Anonymous

@Sid There's no school near to your house?

Sid

I am afraid, no. Nothing good enough.

Avantgarde

The one I sent? @Mostafa

Sid

20:27

There was... Till 10th. After that, I had to switch schools

Mostafa

@Avantgarde No. this []() thing in my message above

Sid

@Mostafa I think there should be a space between the braces

Avantgarde

@Mostafa ok

Anonymous

20:40

@BalarkaSen I can't understand why $|\frac{dT}{d\vec{s}}|$ gives the curvature of a function. $T=\frac{s'(t)}{|s(t)|}$

Anonymous

$t$ is the parameter.

0celouvskyopoulo7

Because it is large for windy curves and zero for straight ones.

Balarka Sen

@Blue If $s = s(t)$ is the parametric curve in $\Bbb R^3$, $T$ is the unit tangent at $s$, isn't it? $dT/ds$ is the rate of change of the tangent.

If the curve is really bendy like 0celo says, the rate of change of the tangent would be very large.

Like, it would change a lot very quickly as you go along the curve.

If it's straight like a straightline, the tangent doesn't change. $dT/ds = 0$. The curve has no curvature.

Anonymous

@BalarkaSen Oh, makes sense. Thanks!

Anonymous

Most physics books give the direct formula without any explanation. :P

Balarka Sen

20:45

Ted has an explanation of all this in a very lucid way in his lectures/textbook.

0celouvskyopoulo7

It's the obstruction to the curve being flat. What more do you want?

Flat/straight. Same thing.

Anonymous

@BalarkaSen Don't tell me about his books. :D I'd need to save my pocket money for three years to even think of buying that book. (Yeah, his lectures are good. I use them nowadays.)

Balarka Sen

His book is impossible to buy, yes.

0celouvskyopoulo7

That book is cheap as far as gen ed books go.

Balarka Sen

@Blue faculty.franklin.uga.edu/shifrin/sites/…

chapter 1 is all you need to know about differential geometry of curves

Anonymous

20:50

I'm slowly getting over my "shyness" of mailing the authors. :P Yesterday I was facing some doubts in Lagrangian Mechanics while reading Jacob Linder's book. I took a chance and mailed him. To my surprise he mailed me back in an hour and clarified my doubts in detail.

Anonymous

@BalarkaSen Ah, thanks!

0celouvskyopoulo7

My advisor told me not to email authors because that gets you on a list of stupid people. Seriously.

Anonymous

@0celouvskyopoulo7 Doesn't matter if I appear stupid if I get to learn something in return.

Balarka Sen

I should shoot a mail to Hatcher sometime, with selfie of mine with his book and a T-shirt written "Allen Hatcher is my homeboy" through it

0celouvskyopoulo7

@Blue If you could see yourself working with them in a few years, it does matter.

I am thinking of a Ricci flow person and a Math GR person.

Anonymous

20:52

@0celouvskyopoulo7 I don't really agree.

0celouvskyopoulo7

Ah, I forgot your years of experience in academia. Sorry!

@BalarkaSen He seems like the kind of guy who would appreciate that lol

Anonymous

@0celouvskyopoulo7 Yeah ;)

Anonymous

@BalarkaSen lol :"D

Anonymous

You should try that, really XD

Avantgarde

You mailed the author of a book?

Anonymous

21:00

@Avantgarde yes.

Avantgarde

Nice

They will most probably reply (if they're not too busy). Everyone likes it when you ask questions about their work.

0celouvskyopoulo7

Again, not everyone...

Anonymous

@Avantgarde Yep. He seemed very polite and took a lot of time to explain the topic to me. Over 2-3 mails. :)

ACuriousMind

I'd say it very much depends on the kind of question.

0celouvskyopoulo7

There is a famous person who wrote papers to make them more confusing. He wanted people to know he could prove things but not actually understand proofs

He then wrote a book which at times is ridiculous. The coauthor helped a lot though

Avantgarde

21:02

@Blue That's quite nice. :)

I'm pretty sure there's another psychological effect named after this behaviour.

@blue so you finally did find a book on classical mechanics?

0celouvskyopoulo7

@ACuriousMind is there a smart name for a two-to-one map? Not a double cover.

Anonymous

@Avantgarde Yeah, I'm reading Jacob Linder's book along with the NPTEL lectures by Prof. Balakrishnan.

Anonymous

Going well so far

Anonymous

Although I have to master multivariable calculus before I can understand Goldstein fully.

Avantgarde

NPTEL lectures are good, though they're not so fun at times. But the material covered is pretty decent.

Anonymous

21:11

@Avantgarde I play them at 1.5x speed. Otherwise they seem too slow. :P

Anonymous

Yup, the content is quite good!

Avantgarde

I can imagine heh.

John Doe

21:54

@Mithrandir24601 I guess from our discussion, it is also clear that we we can only replace the measurement with a unitary operator in that way if the the state we start out with is pure.

0celouvskyopoulo7

22:04

@ACuriousMind halp

wtf

ACuriousMind

@0celouvskyopoulo7 not that I know

@0celouvskyopoulo7 Well, a hyphen is usually a good place for a line break. You need to use a non-breaking hyphen

0celouvskyopoulo7

how do I do that?

ACuriousMind

I don't remember...

I'm not sure that even works in TeX, but it should

0celouvskyopoulo7

I will just write "has one path component"

whatever

0celouvskyopoulo7

22:16

@BernardoMeurer she replaced the battery and now it's fine

Bernardo Meurer

@0celouvskyopoulo7 Is she hot?

0celouvskyopoulo7

can hotness be negative?

Bernardo Meurer

Yes

0celouvskyopoulo7

does negative hotness mean bad?

if so, then -1

Bernardo Meurer

Shame

Told you it was the battery :^)

0celouvskyopoulo7

22:20

TIL PCs have batteries

Bernardo Meurer

@0celouvskyopoulo7 All computers do, it's the CMOS/BIOS battery

it keeps the RTC going and the configurations in the volatile flash

0celouvskyopoulo7

all? Bold statement.

Bernardo Meurer

All normal computers at least

Mostafa

@0celouvskyopoulo7 Note that there is a huge difference between how women see men and how men see women

0celouvskyopoulo7

gross

her personality is what gives her a negative score

I'm not being superficial

Mostafa

22:27

@0celouvskyopoulo7 That's why I didn't post it directly

(Just wanted to remind you that)

Bernardo Meurer

@Mostafa To be honest it's less about age and more about not being a complete fuckwad

Which man tend to be, me included, lol

Mostafa

@BernardoMeurer Even ACM?

Bernardo Meurer

ACM is an AI

0celouvskyopoulo7

ACM is certainly not a man

Mostafa

@0celouvskyopoulo7 He's the He-man.

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