The h Bar

12:03 AM

@SirCumference Hmm... 'looking it up' is (in my experience, in physics) a much more superficial level of understanding than you might think. It can definitely help (and help a lot), but if I haven't spent the hours figuring things out 'the hard way', a 20 minute video (or even the ideas/concepts explained therein) won't stick in my brain very long. Whereas, while I can't remember any of questions I did in undergrad, there's something that seems to have stuck or gotten hardwired into my brain

Sir Cumference

12:16 AM

@Mithrandir24601 What do you mean "the hard way"? Practice?

Tbh I'm spending countless hours each day to get a true intuition on this. I'd really hate to lose that...

Mithrandir24601

@SirCumference Spending hours going mad on infuriatingly difficult questions

Sir Cumference

;-;

I guess I haven't been practicing as much as I could...

But jeez. 24 hours in a day just isn't enough time.

Mithrandir24601

@SirCumference If it were easy, you should do something harder :P so you seem to be heading along the right track ;)

@SirCumference I know people who operated on a non-24 hour pattern in undergrad...

Sir Cumference

@Mithrandir24601 I'd like to be one of those people, but tbh I have to be a wizard to keep up with all this.

Mithrandir24601

@SirCumference Well then, you'll just have to learn to be a wizard :P

you'll be fine - it'll all work out in the end. You might question your sanity more often than not, but you'll get a much better understanding in the process

Sir Cumference

12:24 AM

@Mithrandir24601 True. But so far I've spent the vast majority of my time as an 18-19 year old locked in a room with a book

Or occasionally with other people and a book

0celo7

@SirCumference I was probably trolling

Sir Cumference

@0celo7 ???

0celo7

or I was in my denial stage

it's hard to tell

Sir Cumference

Sep 23 '17 at 15:03, by 0ßelö7

Oh, just jobless.

But 8 stars

0celo7

oh, that

yeah you're an astronomer

Mithrandir24601

12:25 AM

@SirCumference Read Lev Grossman's the Magicians trilogy

Sir Cumference

@Mithrandir24601 I wasn't literal when I said I wanted to be a magical wizard.

@0celo7 So?

0celo7

@SirCumference You shouldn't expect to get a job in your field, directly

Mithrandir24601

@SirCumference I'm not kidding - his explanation of what it's like to go from being at school and finding everything super-easy to an environment where suddenly, everything is nightmarishly difficult and you just don't have the time to even try to learn everything, then on from that into the real world is absolutely spot-on

(along with numerous other superb things that make the trilogy worth reading. Not just the first book, which by itself is nothing spectacular, but the trilogy as a whole is outstanding)

Sir Cumference

@0celo7 True. Do you have any recommendations for an engineering class?

0celo7

heat transfer

Sir Cumference

12:31 AM

Isn't that in statistical mechanics?

0celo7

...and that's why you need to take engineering classes

Sir Cumference

@0celo7 ?

0celo7

your statement is so preposterous that you will basically die in the real world without help

Sir Cumference

I mean I'm not going to have the chance to take too many engineering classes. My schedule's mostly packed with a double major and 2 minors. I'd need to pick wisely

@0celo7 Wait what ;-;

0celo7

double majoring is a scam

Sir Cumference

12:35 AM

@0celo7 I mean it's Math and Physics. Given that many of the classes overlap and a lot of the extra math could help me as an astronomer, it seems like a good choice.

Though I don't see this landing me a job very well...

0celo7

It's not clear that anyone has ever cared about a double major

All it seems to do is make you take more classes that you don't want to take

Sir Cumference

Yeah. But still tho, the Physics major requires up to Calc III, Linear Alg and Diff Eq. It even says "Students who intend to continue Physics in graduate school are strongly encouraged to take more mathematics classes than are required".

And if I'm taking so many, a few more won't hurt much. At the very least, a math major looks better than a physics major.

0celo7

So physics major requires first semester freshman math

How exactly does that line up with a math major?

nitsua60

@0celo7 By that reasoning the major is a scam, because it makes you take classes you don't want to take. Yet behold: many of us actually liked enough classes in one or even two departments that we majored in things without taking a single unwanted class!

Sir Cumference

@0celo7 Well I finished the math requirement last semester...

@0celo7 Well, Analysis can't hurt to know, especially if I want to understand GR well.

0celo7

12:43 AM

I think it might be indicative of some form of mental illness

Sir Cumference

Intro to Topology and Intro to Diff Eq would both satisfy some requirements for the math major, and they're also useful if I want to do cosmology.

0celo7

@SirCumference I think we've been over this. To understand GR like a physicist does, even "well", there's basically no analysis involved.

Balarka Sen

Take topology. 'S fine m'dude

0celo7

Um

I didn't mean to delete that if I did

I tried to edit to say "not possible to take no unwanted classes"

@BalarkaSen It would be point-set.

Sir Cumference

@0celo7 Okay, perhaps. But the other classes would certainly help. And with those, I just need to take Real Analysis I and II and Algebra I and II.

Balarka Sen

12:46 AM

That's why I was objecting earlier but on closer look it's good for the soul

0celo7

@SirCumference Yeah, "real analysis" will not help you understand GR

Unless that real analysis is insane and is Paley-Littlewood theory and other insane things

Sir Cumference

@0celo7 Ok, one class might not. But real analysis sounds so cool. Infinities!

Before that's innuendoized

I mean, Honors Algebra I is just cool because it gives me a new perspective on algebra and geometry

Even though it's ridiculously hard

@0celo7 What's exactly the difference between Real and Complex analysis, btw? Are they that different?

Balarka Sen

Very

Sir Cumference

I'd think working with complex numbers would be much harder and, well, complex

Balarka Sen

In complex analysis being once differentiable means infinitely differentiable

That's the fact which makes complex analysis easier

Sir Cumference

12:52 AM

@BalarkaSen What what

How

Balarka Sen

Hehe

Sir Cumference

So there's only two classes, non-differentiable and differentiable?

Semiclassical

locally, yes.

Sir Cumference

What is this

Balarka Sen

@Sir Let's play a guessing game. Suppose you have a function $f : \Bbb C \to \Bbb C$

How would you define $f'(z)$?

Try to find the right definition.

Semiclassical

12:54 AM

with real analysis, there's enough pathologies possible that when it comes to series expansions it's hard to say a lot in general. with complex analysis, things are nice enough that you can ask how things fit together in interesting ways

Sir Cumference

OK, I'm actually getting sidetracked...

Balarka Sen

That's good, you're being productive. Instead of spending 40 minutes on the meta theory of selecting the right courses you're talking about actual mathematics

Semiclassical

lol

0celo7

@Semiclassical the insane thing is that the interesting objects in real analysis aren't even necessarily continuous...

Balarka Sen

less regularity more power lmao

Semiclassical

12:57 AM

ugh

I guess another way to put it is that, in real analysis, "differentiable" doesn't tell you a lot

0celo7

@BalarkaSen $$\frac{1}{2\pi i}\int_{C}\frac{f(w)}{w-z}dw$$

Semiclassical

whereas in complex analysis it tells you a ton

Balarka Sen

pls stop

Semiclassical

mmm cauchy

Balarka Sen

differentiability in complex analysis is a PDE condition

0celo7

12:58 AM

@Semiclassical it's just elliptic theory in disguise.

the right thing to note is not that complex differentiability is magic

it's that harmonic functions are fucking magic

^^^^

lol

100% true

laplace's equation is great

though I would still elevate complex analysis a bit, since it's talking about 2D harmonic functions in particular and how nice those are

0celo7

@BalarkaSen what is a Poincare geodesic

Balarka Sen

1:02 AM

vOv

0celo7

something something Teichmuller space

idk

too hard

0celo7

1:43 AM

@BalarkaSen "then $M$ cannot carry a metric with quasi-positive scalar curvature" ...do they mean nonnegative lol

@BalarkaSen I need algebra help

What does the following mean: for any finite subset $g_1,\dotsc, g_N$ in $\pi_1(M)$, there exists a normal subgroup $N$ of finite index such that $g_i\notin N$ for all $i$

I know what the words mean, but what does it "mean"

and why does, say, $\Bbb Z^n$ satisfy it

Balarka Sen

2:15 AM

well think about subgroups of $\Bbb Z^n$ of the form $k_1 \Bbb Z \times \cdots \times k_n \Bbb Z$

if you choose $k_1, \cdots, k_n$ carefully you can miss any finite set of elements you have

pick something relatively prime to them etc

0celo7

yeah, I kinda had that already

but what does that condition up there give you

heuristically

what does it say about the group

Balarka Sen

hm

0celo7

@BalarkaSen like I know Morwen will ask me if it's true for his favorite manifold

Balarka Sen

so given any finite set of deck transformations you can pick a finite sheeted cover which does not have those symmetries

something like that

hmmm

I wonder if this holds for the free group. I have a sneaking suspicion it doesn't

Eg $F_2$ say

0celo7

the "finite index" is kind of mysterious to me

@BalarkaSen this spin geometry book is actually amazing

I might have to do some significant reading of it

vzn

2:35 AM

@SirCumference software :P

re the erotic mathematician, saw his 15m intro to his movie today & enjoyed him on colbert wow gotta get his book, amazing website like movie star, like a young Kaku :P o_O vimeo.com/17906654 cc.com/video-clips/xj9d66/the-colbert-report-edward-frenkel edwardfrenkel.com

Balarka Sen

everyone loves eddie boi

0celo7

@Semiclassical I need your EM expertise

i think I have an integral that only an EM master can do

Semiclassical

?

0celo7

@Semiclassical $$\int_{|x|=r}x^ix^j \,d\sigma$$

Semiclassical

hmm

0celo7

2:44 AM

I think it's $\delta_{ij}$ maybe with a factor of $r^{n+1}$

Semiclassical

yeah, that's my instinct as well

0celo7

and some pi's and shit

Semiclassical

yeah, factor of $1/n$ as well

0celo7

@Semiclassical yes!

how did you get this magic

Semiclassical

lol

Because all of the $i=j$ cases together should give $\int_{|x|=r} r^2\,d\sigma$

0celo7

2:47 AM

mm

I think one should consider the matrix $\int_{|x|=r}\mathbf x\otimes\mathbf x$

this should be isotropic, so it's $\propto I_n$

Semiclassical

or, more simply: $$\int_{|x|=r} x^i x^j\,d\sigma =C\delta_{ij}\implies \int_{|x|=r}x^j x^j \,d\sigma = C\delta_{jj}$$

0celo7

then take the trace to figure out what $C$ is, yeah

I did this integral in high school

Semiclassical

right.

0celo7

but I had some bullshit argument I'm sure

I'd like to be a bit more careful here

Semiclassical

right.

0celo7

2:49 AM

then again, I have forsaken rigor already

what's the use in forcing it here

Semiclassical

Am I right in thinking Schur's lemma is relevant here? I'm having vague recollectiosn

hmm, maybe I"m remembering something else

Sir Cumference

@vzn I mean I'm a comp sci minor

0celo7

@Semiclassical Just argue that the matrix is rotationally invariant, and this is only possible if it's diagonal and every eigenvalue is the same

I think that's right

Semiclassical

right

And then yeah trace is the thing to say

vzn

3:07 AM

@SirCumference ok is there any engr that appeals to you? honestly my next highest personal recommendation would be fluid mechanics/ dynamics =D (ps am aware others around here would differ highly...) if you want something more practical try "statics + dynamics"

@BalarkaSen looks like hes dabbled in physics... any idea there?

Balarka Sen

Nope

I think he's worked in the intersection

vzn

seems hes into interpretations of QM + "neo-realism" (ringbauer et al) nytimes.com/2015/02/22/opinion/sunday/… also digital physics nytimes.com/2014/02/16/opinion/sunday/…

Balarka Sen

idk man i dont follow the public figureheads of science

vzn

lol ("idk man") seems a bit )( more than a "public figurehead"...

Balarka Sen

well there are lots of public faces of science who are good scientists

didnt really mean disrespect in that

but eddie boi is definitely a public figurehead of mathematics

vzn

3:16 AM

yeah but theres also a lot of dissing of those (similar) "figures" eg in here, some examples. anyway, with frankel, easy target, lots of snark is justified, so have at it :P

Balarka Sen

i think you're equating snark with meme

eddie is meme worthy

neil degrasse tyson is snark worthy

vzn

lol maybe the subtle )( distinction might have eluded me

@BalarkaSen yes exactly my allusion lol

Balarka Sen

do you see his tweets

they are so r/iamverysmart

that guy might know physics more than me but he's full of crap

vzn

reminds me, trivia: guess where the word snark comes from... :)

@BalarkaSen yeah NdGT says some questionable stuff although havent looked into it closely. probably someone has written it up somewhere tho... met a fan of his at my job, saw his local lecture... geek nirvana

0celo7

@Semiclassical how do you feel about this notational device:

Semiclassical

3:22 AM

that curly bracket?

0celo7

yeah

Semiclassical

I've wondered about that kind of construction myself

I'm never confident it looks good.

dmckee

@SirCumference That can be a hugely frustrating experience, but it is easy to overlook how valuable the hours of struggle actually are. Repeated failure is often a powerful teacher.

Which doesn't mean I don't look back on certain sleepless nights as wasted.

0celo7

3:38 AM

@dmckee Indeed. when I began doing geometric analysis the standard tricks took me hours to figure out and I had many sleepless nights. Now I spend more time worrying that I'm not giving enough details in my writing because it all seems so trivial now

Mikhail

4:01 AM

So the Born approximation is bullshit, right? :-)

Secret

5:09 AM

area51.stackexchange.com/proposals/109272/…

Secret

6:09 AM

1

Q: Does mass only manifest itself only at the instant when the particle wavefunction collapses?

Imagine I'm doing an "old fashion" double slit experiment with buckyball and result showing an interference pattern, I'm wondering what happens to the mass of the buckyball before it hits the screen? Suppose if I'm being granted an one-time miracle exemption from the laws of physics and shrink my...

This question will likely be closed due to too many what-ifs

Sir Cumference

7:10 AM

Astronomers should start measuring parallax with radians

Tanuj

7:20 AM

@JohnRennie hey ! Good Morning :)

@Secret sup !

fireballs

7:49 AM

Does anyone have recommendations for lecture notes on the feynman path integral?

I poked around online and found a couple but nothing super great

Slereah

9:12 AM

top of the morning

Mithrandir24601

@Slereah [people don't actually say that] Mornin'

Slereah

Are you saying I'm not a people

Sir Cumference

9:28 AM

Howdy

Balarka Sen

tappata mannen to you laddies

tips Irish cap

facepalm

maidin mhaith

9:36 AM

lmao

where do you find these things

goddamn

Secret

Kurzgesagt has a new video:

Homeopathy Explained – Gentle Healing or Reckless Fraud?

►

Mithrandir24601

bitesize.irish/blog/good-morning-in-irish-gaelic

@DawoodibnKareem Mornin'!

Slereah

it is a standard meme

There is a wojak of all nations

here is me

Help I'm running out of symbols for functions

Secret

and balarka, regarding about the 4'33", here's a related one also by John Cage, this one has a more obvious content and is zen like:

Ryoanji, One^3 | 2012 | John Cage 100th Anniv. Countdown Event

►

Slereah

I already used $fgh\phi$

all the classics

Dawood ibn Kareem

9:43 AM

Hang on, Unicode has about 100 000 symbols. Just pick one.

Slereah

I can't put the penis hieroglyph for a function

That would be incongruous

Secret

@DawoodibnKareem I actually might lookup later on how many different types of spirals are in unicode, cause I like to notate the most significant unknown variable with a spiral in pen writing

Dawood ibn Kareem

@Slereah I think you could probably use a penis for a couple of different functions.

Secret

📎

fileformat.info/info/unicode/char/5c6a/index.htm

this one is golden

Balarka Sen

@Secret love this

Good video

Slereah

9:49 AM

I actually mean

Secret

This also raised an interesting sociological question: Why are pseudoscientists so good at the human factor while us legitimate scientists don't

Slereah

fileformat.info/info/unicode/char/130b8/index.htm

Ironically it doesn't display on my browser

I guess they were too prudish to make a vector dong

Balarka Sen

@Secret Well that's not true :P

Look at the millions and billions of hanks, cranks and crackpots out there

Secret

I mean, why are they so good at selling their products while we kinda struggle

Balarka Sen

They don't have the basic ability to debate with a person without having a PTSD. That's not characteristics of a stable human being, rather a toppled one.

Secret

9:51 AM

ah i see

Dawood ibn Kareem

The problem is that many, many muppets aren't going to watch that video. Just like astrology and other forms of charlatanism.

Slereah

Law of averages

Most cranks are terrible at selling their ideas and are laughing stocks

Some just happen to be better

Dawood ibn Kareem

I used to teach various software development related disciplines at a certain polytechnic (that I'd better not name). I learnt on my first day in that job that my department also offered courses in homeopathy. I would have resigned if I hadn't been desperate for work at the time.

Balarka Sen

The correct point here is that homeopathy is the earliest example of naturalism in medical science. Yes, the medical value of their theory is close to 0 and with probability close to 1 it's nothing more than a placebo - that dilution increases potency is inconsistent with our understand of modern chemistry.

Slereah

@BalarkaSen Is it

Medical science goes back pretty far

And I don't think homeopathy is that old

Balarka Sen

9:55 AM

Oh not your greek shit again

pls stop that shite

ancient greeks were savages

Slereah

Sorry if they just INVENTED ALL MODERN CIVILIZATION

Balarka Sen

thats why they got rekt by THE HOLY ROMAN EMPIRE

Secret

> that dilution increases potency is inconsistent with our understand of modern chemistry

Indeed, it basically say that if you have pure water you suddenly can heal things in it

Slereah

The Roman Empire was still full of heathens when they conquered Greece

Or do you mean the fake Holy Roman Empire

Secret

On the point of the final section of that video, while the situation is ok for the clinics and hospitals in australia, it is exactly what is depicted in the video when people see a doctor in hong kong. They literally have only 2 hours limit to tell all their symptoms, and then they will be sent out and asked to grab their medicine later

Balarka Sen

9:58 AM

@Secret But, as explained well by the video, what it is is a good example of general treatment of a patient.

Huh, p cool

@Slereah the fake one, yeah

Slereah

Did they ever do anything to Greece

Apart from sacking the easter roman empire

Dawood ibn Kareem

Oh dear! If you study for a Diploma in Homeopathy in my country, our government will subsidise your study, to a total of (equivalent of) US$15600 over three years.

Balarka Sen

hmmm

Secret

@BalarkaSen I think personalised medicine might be getting there but I have not followed the advancement of that field for a while so I am not sure of the specifics

Dawood ibn Kareem

I knew my taxes were being well spent! NOT!

Balarka Sen

10:01 AM

@DawoodibnKareem You're just saying that because you can't get a diploma in homeopathy

Dawood ibn Kareem

@BalarkaSen I bet I could if I wanted to.

Balarka Sen

You're a hater

Slereah

I'm sure I could get a diploma in homeopathy

at the diploma mill

Dawood ibn Kareem

@BalarkaSen I hate charlatanism, yes.

Slereah

I can just send the coupon at the back of the comic book

Balarka Sen

10:02 AM

I dab at you haters

REEEEEEEE

Dawood ibn Kareem

@Slereah Is that where bunnies come from?

Balarka Sen

Is there an explanation of homeopathy using quantum mysticism

That'd be 11/10

Slereah

@DawoodibnKareem No they're from Easter Island

@BalarkaSen almost certainly

Dawood ibn Kareem

Ah yes, but you only need 10^-30 of an explanation for it to be true.

Secret

@DawoodibnKareem There is a few lessons we can learn from the pseudoscience and spiritual people. The issue is that the charlartan to genuine ratio is too high to worth it

Balarka Sen

10:05 AM

@Slereah Did you know

Grothendieck listed Hahnemann as one of the visionaries who saw ahead of their time

Slereah

Who

Balarka Sen

Alexander Grothendieck

Slereah

Do you mean Hanuman

Balarka Sen

the crazy algebraist

Slereah

The monkey king

Oh, founder of homeopathy

Balarka Sen

10:07 AM

lmao

tfw Hanuman invented homeopathy

Slereah

Is he related to Hanuman, perhaps

Balarka Sen

I choked while eating a strawberry

Slereah

Hm

Dawood ibn Kareem

Oops, my mistake. It's over four years, not three. How can someone spend four years of their life studying this nonsense?

Secret

That's a cheetaalatan god or something...

for some reason, Ihave this weird belief that all charlatans are cheetahs

i mean, to first order, they are even spelt simiilarly

Balarka Sen

10:15 AM

page 12

Too long

the 18 mutants

Slereah

@Secret was Grothendieck all along

Secret

lol, I wish I had even half of his mathematical prowess

Balarka Sen

its a DESSIN DE'NFANTS im sure

or however that is spelled

Slereah

If I have seen farther than others, it is because I was standing on the shoulders of giants.
-- Isaac Newton

In the sciences, we are now uniquely privileged to sit side by side with the giants on whose shoulders we stand.
-- Gerald Holton

If I have not seen as far as others, it is because giants were standing on my shoulders.
-- Hal Abelson

Mathematicians stand on each other's shoulders.
-- Gauss

Mathematicians stand on each other's shoulders while computer scientists stand on each other's toes.

Balarka Sen

Love that

Secret

10:20 AM

Both physicists and mathematicians are known to stood on each other shoulders throughout the course of history

Balarka Sen

Hal Abelson's quote is myscorewhenthedrama2good/10

Slereah

Medicine makes people ill, mathematics make them sad and theology makes them sinful. (Martin Luther)

The good Christian should beware of mathematicians and all those who make empty prophecies. The danger already exists that mathematicians have made a covenant with the devil to darken the spirit and confine man in the bonds of Hell. (St. Augustine)

Not wrong

Balarka Sen

It is true

Secret

maths is beautiful, how is it hell

Slereah

"Now we'll prove the theorem. In fact I'll prove it all by myself."

"The highest moments in the life of a mathematician are the first few moments after one has proved the result, but before one finds the mistake. "

Secret

10:30 AM

happens very often when I tried to divide by zero 2 years ago

the mistake then send me to hell

anyway...

THIS GUY IS A HISTORICIAN?!

So..., debrogile is one of those few philosophers that managed to turn his philosophy into physics

Slereah

"Golden rule of deriving: never trust any result that was proved after 11 PM."

Secret

and out comes quantum mechanics as he inspired others

Don't drink and derive, you will crash

Dawood ibn Kareem

To be fair to St Augustine, in his day, "mathematician" was more-or-less synonymous with "astrologer".

Secret

wah...

it also reminds me of a piece of history on how extra dimensions was once thought of as fictional nonsense back then, and then suddenly physicists start to spam it like crazy, finding how useful the idea is

Balarka Sen

I might get 10k rep one day

Secret

10:36 AM

> 8,993 reputation

1007 to go

Balarka Sen

smfin like that

Slereah

"N. had the habit of simply writing answers to homework assignments on the board (the method of solution being, of course, obvious) when he was asked how to solve problems. One time one of his students tried to get more helpful information by asking if there was another way to solve the problem. N. looked blank for a moment, thought, and then answered, "Yes". "

Secret

I often don't just stop at asking whether there are other ways to solve a problem, but to ask about the set of all possible ways to solve the problem and what do they have in common

Slereah

Russian physicist Igor Tamm won the Nobel Prize in physics in 1958. During the Russian revolution, he was a physics professor at the University of Odessa in the Ukraine. Food was in short supply, so he made a trip to a nearby village in search of food. While he was in the village, a bunch of anti-communist bandits surrounded the town.

The leader was suspicious of Tamm, who was dressed in city clothes. He demanded to know what Tamm did for a living. He explained that he was a university professor looking for food. “What subject?,” the bandit leader asked. Tamm replied “I teach mathematics.”

And people say calculus is never useful

Tanuj

Hey people !

Secret

10:46 AM

tanuj: see my ping

Tanuj

I did

Secret

Uncertainty principle? It's not about quantum.

►

Excellant video from 3B1B

it even explains where $p=\hbar k$ came from

-1

Q: Why the nonexistence of a "one sentence layman phrase" for the de Broglie relation $p=\hbar k$?

(My question seems most likely will be considered a duplicate of OP (and possibly 1, 2, 3), but it turns out to be WAY TOO LONG as a comment in OP, and the system has deleted the corresponding chat room due to 15 days of no answers thus I asked here instead for a clarification) Background (All i...

quantum-mechanics momentum relativity

and no, it is not a laymen explanation, but I don't think this can be laymenised

Slereah

"Many of Mostowski's wartime results - on the hierarchy of projective sets, on arithmetically definable sets of natural numbers, and on consequences of the axiom of constructibility in descriptive set theory - were lost when his apartment was destroyed during the uprising. He had to choose whether to flee with a thick notebook containing those results or with bread. He chose bread."

Secret

imagine if he don't. then descriptive set theory would have advance a lot further

Slereah

"In addition to his mathematical and religious interests, Napier was often perceived as a magician, and is thought to have dabbled in alchemy and necromancy. It was said that he would travel about with a black spider in a small box, and that his black rooster was his familiar spirit."

Secret

11:03 AM

Magic is mysterious, and onyl very few understood it

Slereah

"Russian physicist and future Nobel Prize winner Pyotr Kapitsa when he was young was on exchange in the Rutherford laboratory. After the term was over he wanted to stay and work there, but Rutherford wasn't in favor of it. Then Kapitsa asked "what is a usual error margin in your lab's experiments?" Bewildered Rutherford answered "About 3%". "There's 30 scientists employed in your lab. So with your precision you won't even notice me!". Rutherford so liked this what Kapitsa was accepted."

Secret

11:47 AM

0

Q: How Exactly Superluminal Travel Become A Backward Time Travel

This just doesn't make sense, I read everywhere and they all seem to imply that backward time travel is done by superluminal travel. I'm thinking this, imagine i travel at 0,9c, then in my opinion i only travel for 1 day, but for the observer it's been 3 days. Same goes with 0,9999999999999999999...

special-relativity speed-of-light

I repeat:

There is nonlocal influence

There is unreallity

There might be retrocausality
There might be CTCs

But

There is no FTL signalling

Slereah

web.archive.org/web/20061002120436/http://www.math-inst.hu/pub/…

Jesus

and that's only the first part of 7

Slereah

12:20 PM

It even has a chapter on Gödel incompleteness

He uses $\overset{\text{def}}{=}$

How gauche

The best is of course $\overset{\Delta}{=}$

Secret

12:44 PM

Consider a statement involving a countable set and a statement involving an uncountable set. If I were to switch quantifiers in a suitable order, I wonder what will their finite analogues look like and whether they are different...

A better way to phrase is:

What is the essence of uncountability, other than the fact that it cannot inject into the naturals (or other countable sets)

Slereah

There exists a bijection between an uncountable set and some of its subsets

Secret

but countable sets also have that property, so it is not sufficient to distinguish between the two concepts

Other weird things that seemed to be unique to uncountable sets is that they are the only ones that can have positive lesbegue measure, as countable additivity will mean all countable sets are measure zero

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