2:05 PM
@EmilioPisanty no, more like 200 into functional analysis and PDE
@BenNiehoff ikr

in general, I hate when people don't seem to care whether their Latex looks remotely like it's supposed to
it's like, have you read a book?

some people do $sin$ and it's like what

like i said, the acquisition of "taste" is a purely subjective matter

doing $sin$ over $\sin$ is objectively atrocious

says you

2:18 PM
@skillpatrol the nice thing about being objectively correct is that it's independent of me

what?

What?

how can you say "objectively atrocious" is independent of you?

natural law.
@EmilioPisanty why should I buy integral tables anyway

QED

2:28 PM
no

yes

no

perhaps

yes

@0celo7 sinful

2:42 PM
@0celo7 because integral tables are the best

@EmilioPisanty I need to learn ergodic theory right quick
no time for integrals

@0celo7 I have a problem with people who use $\frac{dy}{dx}$ instead of $\frac{\mathrm{d}y}{\mathrm{d}x}$

meh
that one's fine

It makes d look like a variable

to you maybe

2:51 PM
another pet peeve is $*$ instead of $\times$ or $\cdot$

but most people regocnize that it's not
I think you should review calculus :/

$dx$ is fine

@0celo7 It's not about that. But jeez, it's just not pretty
It's like using $log{x}$ instead of $\log{x}$

I think we should use $\mathfrak dx$

But I think we can agree $*$ is the worst

2:52 PM
@Sir well dx is not a function of x

cya

Cya

@0celo7 what about $$(\sum_{i \in \mathbb N} a_i)^2$$
or $$(\frac 12)+3$$

back
@gonenc The worst is when people don't use LaTeX whatsoever
And just write "cos(x)^2 + sqrt(83)"

3:00 PM
they usually write cos(x)^2 too which is somewhat better than nothing at al

@gonenc I don't see anything wrong with that

the brackets?
$$(\sum_{i \in \mathbb N} a_i)^2$$
vs
$$\left(\sum_{i \in \mathbb N} a_i \right)^2$$
but I must admit summation sign was not the best choice here
$$(\int \omega)$$
vs $$\left( \int \omega \right)$$ is better
for that purpose

There's something charming about small parentheses
You're not going to get me with that one

3:17 PM
@0celo7 really? I find them infuriating
except inline parenthesis
I have mixed feelings about them but if \left( \right) is needed inline, then it shouldn't be inline
or instead of $\frac 12$ one can use $1/2$

I have to side with gonenc
Small parentheses are painful

my whole point is you have to take sides

$\tiny{(}\large{1}\tiny{)}$

3:33 PM
It's just notation
Y'all need to chill

1 hour ago, by skill patrol
like i said, the acquisition of "taste" is a purely subjective matter
y'all

Try to defend this notation

Algebraic topology?

No just logic

They have similar effects on GDP, hence are ~

3:38 PM
principia?

yes

has penrose arrived?

Yes

it has
Hey @0celo7, didn't you have a print version of like Sanchez

Yeah
It was in one of those collections of articles

3:44 PM
@Slereah xkcd proposes some modification to your cowboys

Do you want the name?

I do
I use Sanchez quite often

@ACuriousMind the Denali xkcd person reminds me of Trinity
@Slereah I will search my records

@0celo7 Denali?

It is somehwere in our Skype chat
@ACuriousMind female

3:46 PM
@vzn Not really. It was more of the classical, unsolved nature of the problem that catches everyone's attention with that result. I'm no exception. :)

@0celo7 How does "Denali" mean female? Googling tells me Denali is a mountain in Alaska

Autocorrect

twin peeks :P

That's one of the weirder autocorrects I've seen

@ACuriousMind not really!
I just hit the first three letters one to the left
I got the e right I guess
Anyway

3:51 PM
I thought Denali was a river in Egypt

That's the Nile

no, that's denial

No, that's @SirCumference's state of mind

no, that's the twin peaks in alaska

p.s., in addition to atrocious LaTeX, I think I hate philosophy

3:55 PM
why?

I dunno, I really enjoyed it once

aren't you a PhD?

but now it just seems like either meaningless statements or trivialities, dressed in very fancy language
indeed!

Physics still has a phi in its name though

but the worst thing in philosophy is when you try to argue any of it with someone
because they will assume that if you disagree with something, it must be because you didn't understand it
it's like, dude, we're discussing the human condition here...it's like literally the only thing that is totally open to disagreement
(modulo social science, which is super hard to do well, but gives us some actual facts about our condition)

3:59 PM
Would you like to hear my philosophy?
I've been working on it for a while

only if it's short
does it fit into a haiku?

I don't remember how to haiku
5,7,5?

Yeap

Get rid of the libs
Make America Great Ag'n

4:01 PM
Liberals?

I am trapped in a
me help before they

I don't know a finish
The end
It doesn't really work in haiku form

Cambridge is a haiku factory?

no
I'm not at Cambridge anymore

Let's just say there are parts of the population that should be taken by aliens and never returned
I'm not saying that it's good or moral or beneficial. I'm just saying it should happen.

4:07 PM
Why should it happen if it's not good or moral or beneficial?

My philosophy is based on a set of axioms. From these axioms we derive groups of people that MUST be abducted by aliens.
The theorems might not be good, but they follow logically from the axioms, hence are true

True according to those established axioms

For instance, well ordering follows from AC. Well ordering is a moral abomination but AC is true, hence well ordering is actually imperative
It appears to be contradictory but is not

Define: true.

The converse of false
@JaimeGallego I think they're fairly sound
Some of the basic ones are no murder, no rape, no going to high school without a backpack
People who do those things must be abducted
Sandals with long pants, sandals with socks, etc.

4:13 PM
You've actually been working on this for awhile?

Lots of obviously true rules
@skullpetrol I have a list of 30 axioms

Sounds long and involved.

All nihilists too

I have worn sandals with long pants
but Belgium is too cold for that, so I guess I repent?

Do you regret it?

4:15 PM
not really

The aliens are merciful
Well then you're a monster, wtf is wrong with you

it's warm enough that I want my feet to get some air, but not warm enough for shorts

what is the topology of the space of all philosophies

A blackhole.
aka the rabbit hole

@Slereah discrete

4:20 PM
discreet topology
ssh!

are the trivial and discrete topology actually useful for anything

yeah. to know when your space is dumb

@Slereah counterexamples probably

@0celo7 sandals with long pants is okay man

You think Gromov doesn't look like a street urchin, the aliens are coming for you already

4:29 PM
Top zozz

@0celo7 A pure specimen

🤢🤢🤢

I'm curious, can anyone refer me to a good definition of the exceptional Lie groups (especially E8) that doesn't make use of roots or Dynkin diagrams?

it is a very very good group
u might even say

@BenNiehoff Depends on which one. For the E type I got nothing, but $G_2$ is the isomorphism group of the imaginary octonions, for instance

4:33 PM
exceptional

For the E type, I'm pretty sure we only know them by their Dynkin diagrams

$\mathfrak{Exceptional}(E_8) \gg 1$

ah, yes, I have heard that G2 is the automorphism group of the imaginary octonions...I think F4 is somehow related as well
of the E series, even E6 would be nice...

How is the average grad student learning string theory supposed to understand the exceptional groups?

Is it even useful for string theory?
The only use I've ever seen is that weird GUT that has an $E_8$ gauge
which is a fuck huge gauge

4:38 PM
@Slereah $E_8\times E_8$ is one of the two only possible gauge groups for the heterotic string/SUGRA

That's even huger!

Gotta be huge, the other is $\mathrm{SO}(32)$!

Doesn't $E_8$ have like a full byte of dimensions

complex dimensions

256 or something

4:39 PM
248

close enough
You couldn't write it on 7 bits

more or less

The cancellation of the gauge anomaly requires very specific large gauge groups, and only $\mathrm{SO}(32)$ and $E_8\times E_8$ fit the bill

@ACuriousMind how does one prove that those are the only possible groups?
I think BBS say it's trivial or something stupid
Proving uniqueness of a group seems fairly difficult.

Do string theory books have an appendix where they write all the generators, like people do for SU(2) and SU(3)
The million 32x32 matrices

4:40 PM
Especially because E8^2 is stupidly hard to define

I think the issue is that you need groups of a certain dimension

@Slereah nope
They assume the readers will believe them when they say group theory things

I think there's a website that has the generators of $E_8$

@0celo7 You need $\mathrm{dim}(G) = 496$ and a very specific factorization of $\mathrm{Tr}_\text{ad}(F^6)$.

And they're files of several gigabytes

4:42 PM
why would anyone even want the explicit generators of U(8)?

It's relatively easy to see that you can't take a product of groups where that factorization arises if it doesn't already factorize in the individual factors

Why 496?

And then you end up with the options $E_8\times E_8,\mathrm{SO}(32),E_8\times\mathrm{U}(1)^{248},\mathrm{U}(1)^{496}$

Seems random
Do we have a complete classification of Lie groups by dimension?

Turns out Abelian factors spoil the mechanism of anomaly cancellation you got these constraints in the first place from, so they're out (this is a relatively recent insight, 2010 I think)
@0celo7 It comes from the explicit computation of the anomaly polynomial

4:44 PM
Have you done that calculation?

well shit, the Wiki article actually writes down the Lie algebra, which is surprisingly simple

@ACuriousMind that's a big torus

but it's uncited, so I can't tell whether to trust all of it

@0celo7 Sure - the simple Lie groups are completely classified by their Lie algebras/Dynkin diagrams and getting the dimension of a vector space isn't hard.

Umm, don't you need a fuckload of matrices to write down the Lie group?
@ACuriousMind simple?
I know what it means, but I wasn't asking that.
Why should the group be simple

4:47 PM
apparently you take the 120 generators of SO(16) and throw in a Majorana-Weyl spinor of Spin(16) (128 components) and write down some surprisingly simple commutators between them

@0celo7 It shouldn't, necessarily. But if you know what simple means I don't need to explain to you why classifying those suffices :P

@0celo7 I deny that

lol

Reviewing papers is really hard.

@DanielSank the hardest part is that I always get asked to do it when I'm really busy!

4:50 PM
@BenNiehoff Are you ever not busy?

exactly :D

Also, promising that I am asking this entirely out of technical interest, would you mind telling me what needs you have not been able to serve on a Linux system?
I am genuinely interested and will not try to "convert" you.
I just want to know.

If one can decompose any Lie group into simple ones then that's the first time iver heard of that

@DanielSank As I've mentioned several times, the problem is getting all hardware functions to work on the Surface Pro 4

FWIW I use Windows at work for some programs that don't run on Linux. I am not an OS zealot.

4:52 PM
I know that's hard, the SP4 is expensive, and no Linux developers seem to own one, or understand what's important about it

@BenNiehoff Ah yes, hardware compatibility is a definite point where Windows simply works and other OS's are a PITA.
@BenNiehoff Yeah for sure. Makes sense. Thanks.

SP4 uses a very unusual wifi adapter with no published specs, plus there are the keyboard attachment and the Surface Pen

My laptop runs a flavor of Ubuntu. I love it in many ways, but the battery life is terrible and I think it's because the Linux drivers just aren't optimized.

and I use all of those things and expect them to just work
I have heard there are ways to fix battery life for Linux on laptops, but I'm not sure how successful they are

For sure.
Switching topics, I've seen you around a lot lately but I know nothing about you.
Hi, I'm Daniel. I work at Google on superconducting qubits.

4:54 PM
back before I got a Surface, I had a Fujitsu laptop, also with builtin Wacom screen, and I ran Arch Linux and got everything to work just fine
So I definitely know what I'm doing. :)
But the SP4 is just too hard

@BenNiehoff Ah, indeed.
I don't envy you're having to switch OS's.
I guess these days Windows supports unix-y stuff, supposedly. Have you messed with that?
Like, it ships with msys installed or something...

the older laptop originally came with Windows Vista...but when I upgraded the hard drive, Vista didn't know how to read the new block sizes
so, I was forced to install Linux

@BenNiehoff hahahaha nice.
I had a friend who worked at Microsoft.
He said that half way through the dev cycle on Vista, they lost control of the build and had to start over on a lot of stuff.

I tried Windows' Linux-y stuff...it's not as good as Cygwin

@BenNiehoff You have to compile from source for Cygwin though, right?

4:56 PM
no

Oh
Wait I'm confused. The difference between Cygwin and mingw is...
?

oh, since we were doing introductions, I'm a postdoc at KU Leuven. I do string theory

String theory, eh?

aside from that they are completely different things, I don't think I can explain the important differences between Cygwin and mingw

429

I want to make my C++ project cross platform, and I'm considering using Cygwin/MinGW. But what is the difference between them ? Another question is whether I will be able to run the binary on a system without Cygwin/MinGW ?

4:59 PM
oh, I don't use Cygwin for the C compiler...I use it for having Linux shell commands in my CMD window :P
because I don't know DOS and can't be bothered to learn
I'm surprised "explain this paper to me" is a legit question type:
3

Erik Verlinde has proposed a emergent structure of Gravity in a recent paper Emergent Gravity and the Dark Universe Abstract from paper cited above Recent theoretical progress indicates that spacetime and gravity emerge together from the entanglement structure of an underlying microscopic...

@ACuriousMind Are you around?

@BenNiehoff welcome to the chat. have been reading about Verlinde myself lately, citing him in here & am attracted to his ideas esp wrt "emergent properties". plz consider this :) physics.meta.stackexchange.com/questions/7783/…

a ha! I found a resource with some concrete information about exceptional Lie algebras in the e-series (including the higher ones that don't have finite-dimensional representations)
@vzn I'm curious to see how the Verlinde program plays out. I can't say I understand it much.

@BenNiehoff Oh that's totally different.
Mingw is a compiler that takes code written with linux system calls and compiles it to run on Windows.
Cygwin is different, but I'm not entirely sure how.

@BenNiehoff it seems to be relatively new/ somewhat radical wrt est theory, yhave a bunch of links on it, am planning to blog on it soon, Hossenfelder has some blogs on it, also Quanta mag profiled it recently

5:11 PM
@Kaumudi.H: look! My local supermarket has your favourite type of pizza!

Sabine has a paper on it, in fact!

@BenNiehoff have you looked at her paper? am a fan, coincidentally was just reading her blog today wrt simulation hypothesis as refd by aaronson, have blogged on that a bit )( also

@JohnRennie ::tries not to barf::

@DanielSank It's ... erm ... not high on my list of things to try

5:13 PM
@BenNiehoff Personally, I don't think that's a legit question type, but I'm not going to mod-close that question. If people don't want those questions they're gonna have to step up and close them.

I skimmed her paper when it came out, but again, it's pretty outside of what I do, so I can't say I understand much:

lol, that simulation stuff is exactly the philosophy I was arguing about that brought up my earlier gripes ;)
protip: never get into arguments on Facebook :(
2

@BenNiehoff Yeah, Facebook arguments are a rookie mistake.

@BenNiehoff you debated simulation hypothesis on facebook? bummer its not linkable. are you pro/ anti? full disclosure, have leaned pro myself for many yrs & am in good company :P

5:16 PM
I wouldn't call it "debated"

I find the question of whether or not we live in a simulation entirely pointless - how could we ever tell either way? It's just Descartes' demon in a modern disguise.

@vzn; do you have any mainstream views?

user228700

@ACuriousMind to some degree think thats a very valid objection, to another degree there are some proposed, even beginning-to-implement experiments that attempt to isolate "very subtle" anomalies in spacetime fabric so to speak

I expressed my opinion and was called "ignorant", in fact, mostly for not following the writings of Nick Bostrom in excruciating detail :D

5:17 PM
@vzn Yeah. And how could you tell those anomalies are due to a simulation and not due to the world simply being that way?

@ACuriousMind I agree with you, it's a pointless question and we could never tell. This is my "ignorant" opinion. :)

@ACuriousMind the copenhagen concept comes into play. but if there is any "granularity" to spacetime that would seem to be more consistent with a simulation idea that involves discreteness at very infinitesmal levels

Looking for anomalies is good. That's science. Waffling about us living in a "simulation" is not

@ACuriousMind (admittedly/ concede) there is a lot of (popsci) hype over the simulation hypothesis, in this way its much like AI lately. it didnt "entirely" help that recently elon musk has endorsed it... o_O

5:20 PM
Highway Robbery!

@vzn "More consistent" in what sense? Why can't the world be "granular" without being a simulation? You can't make any sort of likelihood arguments here because our sample size of universes is exactly 1.

to me the only physical thing that could falsify the "simulation" hypothesis is the existence of an oracle: a physical system or process that produces results that are intrinsically incomputable

It's not even a hardcover

who cares? live, eat and die

@JohnRennie I have a veyr weird bug

5:21 PM
Has it switched 'y' and 'r' on your keyboard? ;P

@BernardoMeurer not contagious I hope :-)

@ACuriousMind the analogy is analog vs digital computing. agreed its a very abstract concept. it would take a long time for physics to come to investigate it seriously. but it seems many of the concepts are already present in QM & other areas of physics. & lets not disregard all the high profile proponents incl nobel prize winner 't Hooft

Ah, as usual you have no actual argument to make, I should've known.
6

@ACuriousMind not everything reduces to argument :(

@vzn I think you'll find all of science does ...

5:23 PM
An argument about argument? This is a job for ...

@BalarkaSen Why is "eat" distinct from "live"?

@JohnRennie science intrinsically involves hypothesis/ conjecture and some tend to downplay that in "argumentative" moments.

@ACuriousMind You could inject nutrients into your blood matrix style

@ACuriousMind you could easily eat stuff which makes you die

not very tasty

5:24 PM
@0celo7 an obvious/ longtime fan of the simulation hypothesis but who does not admit it :P

Not really

@BalarkaSen I could also do lots of other stuff in the course of "living" that'd kill me
Why is eating special?

Because eating is good
I don't think anyone denies eating is good

@BalarkaSen Isn't it "Live, laugh, love"? :P

5:26 PM
no

@0celo7 I'm neutral towards the concept of eating :P

@ACuriousMind Fine, don't eat. Live and die.

no taxes

if you don't pay taxes the government will kill you

@BalarkaSen I will :)

5:26 PM
@BenNiehoff Code, sleep, erm ... can't think of a third option right now

@BenNiehoff there is no laughter or love in this blackened heart

@ACuriousMind you're an AI, no one asked you :P
Balarka :(

@0celo7 yeah maybe thats why he doesnt want anyone to investigate simulation and find "the man behind the curtain" :P

he's not that sinister

@0celo7 dope song

5:31 PM
@BalarkaSen Let $(f_n)\subset L^p(\Bbb R^d)$ with $f_n\to f$ pointwise a.e. and $||f_n||\to ||f||$. It's known that $f\in L^p(\Bbb R^d)$. For $\epsilon>0$ can one find $K\subset\Bbb R^d$ compact and $n_0\in\Bbb N$ such that for $n\ge n_0$: $$\int_{K^c}|f_n|^p \, dx<\epsilon?$$

That's an interesting question.

It's clear this can be done for each $n$, but why can one choose $K$ uniformly?
The idea here being that if $f_n$'s norms converge and it converges pointwise, then the masses of $f_n$ get concentrated in some compact set $K$ for large $n$.

I don't know actually.

@BenNiehoff SE arguments are not any better :( o_O
@JohnRennie the standard model is right + the standard model is an approximation of reality & anomalies aka "new physics" lie beyond it
@Kaumudi.H huh?

OK. Today's xkcd is pretty funny. But you have to sing to get the full effect. With your best fake Eye-talian accent. Unless you really are Italian of course, in which case you should use a real accent.

5:42 PM
@dmckee what is a fake Eye-italian accent?

@yuggib There was a while when the scary immigrants who were ruining our great country (that is the USA) were those dirty, Catholic, Italians who were living in groups int he slums and not learning our language and taking our jobs and all those other things that worry certain people so very much.

@yuggib see above question with the integral please

@dmckee yeah, like Sacco and Vanzetti...those anarchists

One the ways that "regular" Americans (meaning the Scots and Irish and Poles and other immigrants who'd been here a little longer) had of pointing out the difference was by intentionally mispronouncing the adjective: Eye-talian.

@dmckee ok, I see

5:45 PM
And of course, putting on an over-wroght version of the accent.

@dmckee I'm not sure how singing in that accent makes the joke about emojis better?

@ACuriousMind I see a newer one, now.

@0celo7 either there is a minus f in the formula, or it does not seem ok

Do you have a counterexample?

your $f_n$ is not converging to zero

5:48 PM
The integral is over the complement of K

I could not see it

@dmckee Ah. That one I don't get at all, probably because it don't know what song it's referencing

@ACuriousMind That's amore

::facepalm::

5:50 PM
a song that get essentially any italian ashamed
at least as much as the killing of Sacco and Vanzetti should get Americans ashamed

A real American is never ashamed

@yuggib Rubbish. Anyone who finds themselves shamed by a catchy but essentially throwaway song urgently needs (a) a sense of proportion and (b) a sense of humour!

@JohnRennie it is an unwillingly hymn song to awful stereotypes
(or maybe a willingly hymn song to awful stereotypes)

@JohnRennie Macarena!

@yuggib the claim is trivially true with f-f_n because f_n goes to f in Lp
That's what I'm trying to prove

5:55 PM
@0celo7 to me, the claim seems also true for any fixed $n$ because $f_n\in L^p$

Yeah, but it needs to hold for all large n
I'm not sure it helps prove the result anyway. There might be a typo