The h Bar

0celo7

1:46 AM

How To Make Traditional Butchers Faggots.TheScottReaProject.

►

0celo7

3:41 AM

@ACuriousMind Does completeness of a metric space imply the Heine-Borel property?

I know Heine-Borel implies completeness.

And I know it's true on Riemannian manifolds...

user116211

4:16 AM

-4

Q: How stephan hawking became great physicist with playboy addiction?

I know he is addicted to playboy magazines, which definitely make him dumb. but he became great physicist. I too addicted to porn & playboy magazines, it is so difficult for me to concentrate on my education, then how stephan hawking became great physicist ?

soft-question

user116211

Mark this.

user116211

OP needs some rehabilitation.

0celo7

hehe

vzn

lol, 404 already. but googled it just for amusement. have no idea what the poster is referring to, maybe its some urban legend or completely fabricated... nearest thing google finds (apparently) is this thorne-hawking-preskill bet involving penthouse magazine. en.m.wikipedia.org/wiki/… and there was also a playboy interview years back.

@0celo7 you might have to rethink some of your rapper affinity because theyre always getting into trouble. or maybe thats the point? thedailybeast.com/articles/2016/06/29/…

0celo7

@vzn I pretty much despise rappers as human beings.

But they make good music.

vzn

4:31 AM

May 21 at 15:33, by 0celo7

Chris Brown is actually a good rapper

0celo7

Yes?

vzn

@0celo7 actually thought brown was repentant after his rihanna fiasco but looks like he cant control himself, or maybe drugs are scrambling his brain, and/or both etc...

0celo7

Good rapper and decent human being are mutually exclusive.

Lil Wayne spits fire but is a degenerate scumbag.

vzn

@0celo7 maybe consider trying something else sometime, say flamenco :)

0celo7

No thank you

vzn

4:34 AM

knew youd say that. hey maybe the gf might like it, could be a good/ plausible excuse/ cover story eh?

Anubhav Goel

@ACuriousMind Please respond to my comment here physics.stackexchange.com/questions/257454/… .I am very curious to know what I did wrong.

0celo7

Good lord -5 on an accepted answer

on a -14 question

yeesh

Anubhav Goel

That was because of bad language of OP

His arguments were quite embarrassing

I don't know if I should delete my answer or not. Although I had -5, I got positive reputation from post. I also don't know what's wrong in my answer. So, I can't decide anything.

user116211

@AnubhavGoel You can't since it is accepted.

Anubhav Goel

Oh!!!!

That's bad

But, it shows delete option and has 1 vote to delete too.

vzn

5:22 AM

in theory salon, 54 secs ago, by vzn

ArXiv preprint server plans multimillion-dollar overhaul / nature

John Rennie

6:37 AM

@AnubhavGoel First note that Astrophysics Math is an unrepentant crackpot. Just have a look at his previous questions. I have several times invited him to discuss the matter in the chat and he always ignores me.

Physics Meta

0

Q: precipitate duplicate declaration

This question Thus, what mediates the electric interaction between two particles which in the question essentially asks: QTF experts say that there are no virtual particles, they are just a calculation trick. So, ok, no particle mediates the electrostatic interaction, what mediates it then? ...

discussion

John Rennie

Re your answer: none of the downvotes are mine, but I think your answer is so confused as to be largely meaningless.

At the moment the answer is giving you a net -2 score, +10 up and -12 down. If you want me to vote to delete it on your behalf I will do.

Slereah

7:14 AM

Hello

user54412

@JohnRennie +15 accept

John Rennie

@ChrisWhite Ah yes. So that's a net +13 for the privilege of having your answer accepted by someone who is uninterested in anything but having their own views confirmed.

ACuriousMind

9:06 AM

@AnubhavGoel My comment there still stands - most of what you wrote doesn't actually mean anything. RonMaimon's answer to the other question is also wrong - a photon does not possess a rest frame.

@JohnRennie Let's just delete the question altogether. There's no point in having it around.

John Rennie

9:29 AM

@ACuriousMind I had already voted to delete the question :-) We just need one more like minded person.

Emilio Pisanty

10:55 AM

@JohnRennie Yeah, I can oblige.

With high-rep users of that sort I end up wanting the bad posts to remain, mostly as a sign of just what their contribution is. But here that's not a problem.

Slereah

11:39 AM

The factored form of the Krasnikov metric is quite suggestive

$$ds^2 = -(dt - dx) (dt + k(x,t)dx)$$

v. suggestive

Hello the danu

Junaid Aftab

11:53 AM

How good is: reference.wolfram.com/language to learn Mathematica for someone with no experience with programming.

I basically need to learn it to do numerical optimization, numerical integration etc. and make fancy graphs after having derived the results.

The sections appear to be in this order. The first four of them.

Views?

David Z

@JunaidAftab fairly useless, I would say. The documentation is optimized for cases where you already understand how to use Mathematica (not quite the same thing as knowing computer programming) and you already know what sort of mathematical tool you want to use, but you need to figure out how it's implemented in Mathematica.

Slereah

Mathematica isn't excessively hard to use

If you can do math

David Z

That's all relative

Slereah

Oh no

Wave equation of two Krasnikov tubes isn't separable at all

Like the least separable thing

Though I guess it might be doable if the two tubes are far enough apart

That we may consider them separately

Slereah

12:22 PM

Oh my stars

Even the 2D case with one tube is horrible

I should rewrite it in terms of like

Fancy functions

Oh wait

$\sqrt{-g} = \frac{1+k}{2}$

That simplifies things

0celo7

@Slereah Danu doesn't like you very much.

He likes ACM and that's about it.

But then again @ACuriousMind is very likable

Slereah

12:38 PM

Nobody loves you, tho

Balarka Sen

:P

0celo7

@Slereah That's not what your mom said.

ACuriousMind

Does anyone know of a refutation of this paper? I've been looking into it for two hours now and I don't know which formalism does which time ordering why anymore.

Slereah

I have a witty retort but I think I'm risking banishment if I say it

ACuriousMind

And the only P.SE question about time ordering and time derivatives isn't any help either.

0celo7

12:41 PM

@Slereah go for it

Savage!

Slereah

So anyway the KRasnikov tube is some horrible shit to compute the wave equation on

unless things simplify in the end, hopefully

It's a 2D linear PDE tho, I am hopeful it should be doable

ACuriousMind

The only other thing I can find it Lubos being uncharacteristically cautious about it, which does not bode well

Slereah

When you say "cautious", does that mean he called it an abomination of nature and an insult to all of science all the way back to Ancient Greece

ACuriousMind

@Slereah No, I mean that he didn't call it that.

0celo7

@ACuriousMind just @ Danu an Qmechanic, no one else has a chance

ACuriousMind

12:45 PM

The paper also has no citations I can locate, which makes me think I'm missing something rather obvious about it

I mean, if the standard derivation of gravitational anomalies were false then the whole "anomaly cancellation" business of SUGRA and string theory just collapses

There is too much internal consistency of the anomaly results for me to believe it's false, but the point about the $T$ vs. $T^\ast$-ordering appears to be valid to me

Slereah

Well, equation is shit but at least things factor somewhat

0celo7

@Slereah Pretty sure the "doable" equations are a set of measure zero.

Slereah

Well

It's second order linear in 2D

I think I should at least get a solution, even if not closed form

eqworld.ipmnet.ru/en/solutions/lpde/lpdetoc2.htm

ALTHO

That's a pretty small set of solutions

I am alarmed

Hopefully I can use some Fourier transform for it

Since the only functions are mollified gate functions and mollified heaviside functions

Those sounds mightily fourier transformable

Some of them are inverses, tho, bad sign

Also there's a giant factor of $1/(1+k)^2$ that I can get rid of, which is nice

Junaid Aftab

1:06 PM

@DavidZ and others: how should I go about getting acquainted and learning Mathematica then?

Slereah

$$\frac{1}{1+k} (-\dot k k \dot \varphi + k' \varphi' + \frac{1-k}{2} (\varphi' \dot k + \dot \varphi k')) + 2 [\partial_t (-k \dot \varphi) + \partial_x (\varphi') + \partial_t (\frac{k-1}{2} \varphi') + \partial_x (\frac{k-1}{2} \dot \varphi)]$$

The equation to solve

Halp

Worst part is that the equation is basially Minkowski space on most of the spacetime

Except for the interfaces

But I'm pretty sure those are pretty important

0celo7

1:25 PM

How many charts cover your manifold?

Slereah

One.

It's $R^4$

Well, $R^2$ here

I guess for a start, I can do the analysis for an ETERNAL KRASNIKOV TUBE

Where the tube has existed for all times

Let's just say the aliens left it behind

0celo7

1:42 PM

Sounds like vagina euphemism.

Slereah

$$\frac{k'}{1+k} \varphi' + k'(\frac{1}{1+k} + \frac{1}{2}) \dot \varphi + 2\varphi'' - 2k\ddot \varphi + (k-1) \dot \varphi' = 0$$

Seems a bit more reasonable

Wait, something is fishy

$k = 0$ outside of the tube, so that would be... $2\varphi'' - \dot \varphi ' = 0$

It should be the wave equation :V

Oh well, it's something of that form, anyway

I shall do the details this week end

0celo7

@JohnRennie Why are all of my shoes giving my blisters all of a sudden?

Are my feet swelling in the heat or something

@Slereah is $k$ a function?

Slereah

It is

For the eternal one, it is $1 - (2 - \delta) \Pi_\epsilon(x)$

0celo7

@Slereah We should read a topology book

Get smart on it

Slereah

$\delta \in (0,2]$ and $\Pi_\epsilon$ is some mollified rectangle function

0 outside of $(-1,1)$, 1 inside $(-1 + \epsilon, 1-\epsilon)$, and smooth in between

I could probably use like a gaussian for it really

Or the actual rectangle function, but then I'd get deltas in my equation

Not sure it's a good idea

yuggib

1:56 PM

@Slereah your monologues are getting more boring ;-P

Slereah

Well gee maybe answer me then

Then it will be a dialog

yuggib

I doubt that anybody cares so much about krasnikov shits

;-P

Slereah

Why not

It is pretty great

and you can make spaceships with it

Pew pew

laser noise

yuggib

I'm not an engineer

I am not fascinated by spaceships

:D

I am more fascinated by contravariant functors (and I am not fascinated by them)

Slereah

I'm sure the Krasnikov metric is the functor of something

ACuriousMind

2:01 PM

@yuggib :D

user116211

Is it on-topic?

user116211

0

Q: How to prove two methods are "similar"?

We are testing two imaging machines. One of the machines has been validated numerous times. However, we built the new machine and we need to prove that it is similar/comparable to the validated machine. So, the machines image a certain tube and determine a physical property. With several image l...

soft-question research-level statistics imaging

user116211

@yuggib: o/

yuggib

\o

0celo7

@yuggib I'm not either

kevin Tah N.

2:13 PM

I have an issue with terminology

ACuriousMind

@kevinTahN. Who doesn't? ;)

0celo7

2

A: The role of the affine connection the geodesic equation

You're on the right track, but there's more that can be said. For an introduction to this topic, I highly recommend Sean Carroll's Spacetime and Geometry, which I'll follow below for the purpose of illustrating where that $\Gamma$ comes from. The book grew out of lecture notes, the relevant chapt...

@ChrisWhite That's not how the affine connection is defined...

kevin Tah N.

Is there some difference between saying things like bulk to bulk, and boundary to bulk, and saying correlation functions?

ads/cft

?

I am looking at some papers now

0celo7

The affine connection is a distribution on $TM$

David Z

@MAFIA36790 I don't think so

P.S. Don't ever edit the soft-question tag on to a question that doesn't have it (unless you know what you're doing well enough to break this rule)

0celo7

2:14 PM

Hmm, although that raises a question

user116211

@DavidZ noted

0celo7

@ACuriousMind How does metricity and torsion-free present itself in the distributional approach to connections?

ACuriousMind

@0celo7 There is more than one definition for most mathematical objects.

yuggib

@0celo7 you're not (yet) an engineer

ACuriousMind

@0celo7 Uh...just define the connection form corresponding to a distribution and apply the usual definition?

0celo7

2:16 PM

@ACuriousMind wat, I mean without that

How does the horizontal bundle carry that information

user116211

@DavidZ So, when should I use that tag?

ACuriousMind

You do know that there is a bijection between connection forms and horizontal distributions, right?

0celo7

Sure

kevin Tah N.

I am going to ask something stupid , I am not taken any ads/cft classes, so does <phi(x_1),phi(x_2)> mean bulk to bulk , or boundary to bulk greens or are these different things all together, not some correlation functions?

David Z

@MAFIA36790 never

0celo7

2:18 PM

then why does it exist @DavidZ

ACuriousMind

@kevinTahN. I don't think anyone except perhaps Danu here knows anything about AdS/CFT

user116211

@DavidZ okay?

kevin Tah N.

oh i see lol

David Z

@0celo7 it's one of those tags that people always create in the early days of any SE site to try to justify questions that aren't really on topic but are fun, or something

0celo7

@ACuriousMind So the information of metricity and torsion-freeness must be contained in the horizontal distribution, right?

what's the mechanism behind that

ACuriousMind

2:20 PM

@0celo7 Yes. In the way that the connection form associated to a metric and torsion-free connection is metric and torsion-free in the usual way

David Z

It's a fairly good rule that any time you think a question deserves the soft-question tag, you should just vote to close it as off topic instead. There's like a 99% correlation between the two.

user116211

@DavidZ: Can't we burninate it then?

0celo7

@ACuriousMind that's not very satisfying!

ACuriousMind

@0celo7 I expected that :)

David Z

Maybe we should, but I guess some people still want it around, or something. You could check on meta, I'm sure there's some record of this debate.

Slereah

2:21 PM

@DavidZ Plebs out

ACuriousMind

I don't know whether there's a natural notion of metricity or torsion-freeness for the distributional approach, but I don't think so

David Z

I have seen just a few questions (in the entire history of the site) that were on topic but it still made sense to tag them soft-question

ACuriousMind

And yet, 1047 questions carry it.

Balarka Sen

@0celo7 Hmm?

0celo7

@ACuriousMind Does a metric connection make sense for an Ehresmann connection or just a Koszul connection

John Rennie

2:22 PM

@0celo7 why did you post a picture of faggots?

0celo7

@BalarkaSen see the discussion with me and ACM

David Z

ok I'm off for now

0celo7

I want to know how the horizontal distribution associated with the Levi-Civita connection shows metricity and torsion-freeness

@JohnRennie It's a video brah

Balarka Sen

I dunno any Riemannian geometry, sorry.

ACuriousMind

@0celo7 I would bet that you need a Koszul connection or an Ehresmann connection with a solder form.

John Rennie

2:24 PM

@0celo7 then why did you post a link to a video describing how to make faggots?

yuggib

@BalarkaSen riemannian geometry is even more boring that other geometry

0celo7

@JohnRennie I think it's an interesting dish.

@yuggib how dare you

Balarka Sen

I think Riemannian geometry is pretty cool, from the little I know about it.

John Rennie

@0celo7 It's a very tasty disk if made well, and it's a traditional dish in the UK. I was just a bit surprised to see you post it here ...

0celo7

@BalarkaSen I want to derive the postulates of Euclidean geometry given topology $\Bbb R^2$ and vanishing curvature form

It's pretty hard because Euclid didn't define stuff properly

ACuriousMind

2:27 PM

Not this again :D

0celo7

@ACuriousMind I will have to prove

THE FROBENIUS THEOREM FOR PDEs

Balarka Sen

I dunno what a vanishing curvature form is.

0celo7

@BalarkaSen 0 Riemann curvature

yuggib

so boring

Balarka Sen

Yeah, but I don't really understand curvature.

0celo7

2:28 PM

$\nabla_X\nabla_YZ-\nabla_Y\nabla_XZ-\nabla_{[X,Y]}Z=0$ for all $X,Y,Z\in\Gamma(TM)$

@JohnRennie I've been watching a lot of cooking videos lately

@BalarkaSen it's just the obstruction to being locally isometric to Euclidean space

@yuggib be quiet

yuggib

@0celo7 nah

Balarka Sen

Euclid defines stuff just fine.

0celo7

@BalarkaSen not in a differential geometric context!

yuggib

you and @Slereah always annoy everybody with your useless stuff

0celo7

> 1. A straight line segment can be drawn joining any two points.

ACuriousMind

2:31 PM

@0celo7 ...I thought you don't have a kitchen?

yuggib

;-P

0celo7

Proof. $\Bbb R^2$ is a complete metric space. Apply Hopf-Rinow.

@ACuriousMind I don't

I might have to find an apartment though, I'm really missing cooking

ACuriousMind

@0celo7 Then why are you watching cooking videos?

0celo7

@ACuriousMind It's called "being bored"

Balarka Sen

Dude you're the alternative universe version of Bourbaki who likes differential geometry instead of algebra, you know? :P

3

0celo7

2:33 PM

> 2. Any straight line segment can be extended indefinitely in a straight line.

ACuriousMind

lol, I've never been that bored

0celo7

@ACuriousMind I actually find it genuinely interesting.

ACuriousMind

@BalarkaSen That is eerily accurate :D :D :D

0celo7

Proof.

Hmm, what is the proof

Just use analytic geometry?

I guess prove that geodesics in $\Bbb R^2$ are always inextendible

I'm not sure how I would do that besides just writing them down.

yuggib

@BalarkaSen well bourbaki knew better

than doing diff geo

0celo7

2:34 PM

@yuggib just shut up

@BalarkaSen Well the problem is that lots of Euclidean geometry becomes trivial once you introduce coordinates

And I'm not sure how he defined $\Bbb R^2$

Balarka Sen

He didn't.

ACuriousMind

He didn't!

0celo7

> 3. Given any straight line segment, a circle can be drawn having the segment as radius and one endpoint as center.

Balarka Sen

High fives, @ACM

0celo7

Now this is interesting.

ACuriousMind

2:36 PM

@BalarkaSen \o

0celo7

One can simply do analytic geometry and write down the equation...

Or perhaps use some theorem on geodesic spheres and use the fact that $\exp$ is the identity...

But then you're just doing the proof in the tangent space which is $\approx$ the space anyway

So that's trivial

> 4. All right angles are congruent.

Hmm, now I don't even know what congruent means

So that might be hard to prove :P

ACuriousMind

I'm having flashbacks, you already did this once.

0celo7

Does anyone know what this could mean?

ACuriousMind

And ran into the exact same problems.

0celo7

@ACuriousMind Really?

yuggib

2:38 PM

@0celo7 one day you will understand...

0celo7

@ACuriousMind Which problems

ACuriousMind

@0celo7 That depending on how you translate the axioms into your language, some become trivial or non-sensical.

Balarka Sen

I'd really enjoy being in this conversation if I didn't have work to do, so have to leave.

0celo7

@yuggib oh, so people like Chern and Weil figured out they wasted their lives on their deathbeds or something?

> 5. If two lines are drawn which intersect a third in such a way that the sum of the inner angles on one side is less than two right angles, then the two lines inevitably must intersect each other on that side if extended far enough. This postulate is equivalent to what is known as the parallel postulate.

The dreaded fifth postulate.

The proof of this will be tricky indeed.

yuggib

@0celo7 Weil did algebraic geometry

not riemannian geometry

0celo7

2:40 PM

I'm at work and do not have a Riemannian geometry text zur Verfügung.

ACuriousMind

@0celo7 They did not share your dislike of cohomology :P

0celo7

@yuggib Chern-Weil theory has implications for Riemannian geometry

yuggib

so?

0celo7

@ACuriousMind I do not understand it, I don't dislike it

@yuggib seriously, why would you say what I like is boring and shit if not to piss me off

Well, I seem to recall a theorem of Riemannian geometry along the lines of:

ACuriousMind

@0celo7 Why do you always say you think QFT is boring and shit if not to piss me off?

yuggib

2:42 PM

^

0celo7

The minimal distance between two submanifolds in a complete manifold is the length of a geodesic orthogonal to both submanifolds

yuggib

I genuinely think that geometry in general, and riemannian in particular, is boring

0celo7

@ACuriousMind because you don't look up to me

it's different

The proof is probably via some arc length functional variation thingie

ACuriousMind

@yuggib What about geometry that's dual to algebra, like locally compact Hausdorff spaces and commutative C*-algebras?

yuggib

@ACuriousMind that's more topology than geometry

ACuriousMind

2:46 PM

Hm...what's "geometry" for you then? Everything with manifolds?

Is algebraic geometry geometry? :D

yuggib

@ACuriousMind algebraic geometry is geometry, manfiolds are geometric, homology/cohomology are geometry,...

topology is not geometry ;-)

functional analysis is (mostly) not geometry

Mike Miller

spectral triples and C* algebras of a foliation exist

0celo7

what does that even mean

yuggib

@MikeMiller non-commutative geometry is geometry

ACuriousMind

@yuggib (co)homology are geometry but topology is not? oO

yuggib

2:49 PM

@ACuriousMind indeed

ACuriousMind

Then algebraic topology is geometry, I guess.

Mike Miller

lol

0celo7

How do you even define "inner" and "outer" angle in Riemannian geometry

yuggib

@ACuriousMind it is at the boundary between topology and algebra of course, but it is mostly used in geometry

as far as I know

0celo7

and where does curvature come into play...

probably just that the geodesics are straight lines

@MikeMiller do you know how to answer my levi-civita question?

29 mins ago, by 0celo7

I want to know how the horizontal distribution associated with the Levi-Civita connection shows metricity and torsion-freeness

ACuriousMind

2:52 PM

@yuggib I see

I guess I would share your broad definition of geometry but not your dislike of it ;)

(neither do I share 0celo7's fervor :P)

yuggib

:-D

0celo7

It's not fervor

yuggib

let's say that I would not make it my research topic

0celo7

If it were I would be reading the geometry book in my backpack instead of looking at cat pictures

yuggib

but I respect it

Mike Miller

2:54 PM

@yuggib That doesn't really make any sense. Sorry.

yuggib

@MikeMiller why?

Mike Miller

There is no sense in which it's true. You also seem to be ignoring the concept that topology in and of itself is a discipline, so that the only two places for algebraic topology to fit are "algebra" and "geometry". (And even in the former, equivariant homotopy theory has had group theoretic ramifications.)

@0celo7 It's an interesting question.

yuggib

topology is a discipline that is not constituted solely of algebraic topology

0celo7

@MikeMiller But one for which you do not know the answer?

Mike Miller

Sure, differential geometers need to know some baseline of algebraic topology (the minimum level everyone needs to know was probably finished up sometime around 1960; sometimes there are more specialized uses). But it's evolved more or less entirely on its own to ask questions that it inspires itself.

@yuggib oh ok my bad

yuggib

3:00 PM

I use plenty of topology, but never algebraic topology for example

but it seems to me that in geometry many concepts of algebraic topology are used

but it is not something I know so well, so I may be wrong

0celo7

@MikeMiller And also, how does the connection on the frame bundle show metricity and torsion-freeness?

(and its associated distribution)

hmm, wait

I know connection on G-bundle --> connection on associated vector bundle

Can that arrow go the other way too?

Mike Miller

@yuggib Again, mostly old ideas, though some people are trying to use eg Lie groupoids to some minor success (which I would hardly call particularly new). The parts of differential geometry for which one sees stable homotopy theory etc are spare. You do not actually need to explain to me what topology is and consists of.

@0celo7 Consider the Grassmann bundle $\text{Gr}_n(TE)$, where $E$ is the total space. The metric you have flying around should define a metric on this, and the horizontal bundle is a section $\sigma: M \to \text{Gr}_n(TE)$. I suspect the condition that your distribution is metric-preserving is the condition that $\sigma$ be an isometric embedding. But I don't know.

Yes, that arrow is a bijection.

0celo7

Grassmann bundle o.o

@MikeMiller Would Ted know for sure or is this even MO material?

Mike Miller

Have you already checked Kobayashi-Nomizu?

0celo7

3:17 PM

@MikeMiller No, it's at home...but I'll do that.

Mike Miller

If it's not in there, it doesn't have an obvious/standard answer.

0celo7

@MikeMiller KN doesn't have everything

I failed to find the statement that curvature is an isometry invariant anywhere

Mike Miller

What? That wasn't what you were asking at all.

0celo7

I know

I'm just saying KN doesn't have everything

Mike Miller

I'm not engaging with this.

2

0celo7

3:23 PM

What?

Slereah

dropbox.com/s/gbnlib7mk103yyg/…

What is this madness

0celo7

Mathematicals

Why did someone star that

Can the person who starred that explain what he meant

Mike Miller

They give definitions of both torsion and what it means to be a metric connection. Torsion is defined in terms of the connection 1-form on the bundle. Being a metric connection is defined as being the connection induced from the connection on the O(n)-reduction of your bundle.

This is immediately shown to be equivalent to saying that g is parallel.

Then I stopped reading.

0celo7

page please?

Mike Miller

I closed the book. Look in the table of contents, which is how I found it.

0celo7

3:32 PM

@MikeMiller What did you mean with the "engaging" comment

vzn

3:50 PM

what can a phd physicist do with ML / reddit

Robust Bell inequalities from communication complexity / La Plante et al

↑ some very deep analysis/ broad survey. esp like the attn to the "abort" idea which seems to indicate "event not measured"... think its groundbreaking/ crucial. also attn to detector efficiency, great stuff

user54412

4:30 PM

@JunaidAftab You know, the dedicated Mathematica site and associated chat room can probably help you out more than us.

user54412

But I'll add my 2 cents: Probably the best way to get into any language is come up with simple problems to solve in it. Note that Mathematica is pretty terrible with numerics and data -- it was designed as a symbolic calculator above all else. Sure, it probably has the functions you want, but the syntax and general feel of the program are... weird... when it comes to numerics.

user116211

user54412

@ACuriousMind It has one citation: adsabs.harvard.edu/cgi-bin/…

user218912

4:48 PM

woah that's a lot of removed messages.

Slereah

If a spacetime if conformal to Minkowski space

Does that mean that the eigenvalues o the metric are [-f(x), f(x)]

Such that $g = f(x) \eta$

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