The h Bar

John Rennie

18:00

@BalarkaSen what do rocket scientists say when they want to say something isn't complicated?

ooolb

@Blue have fun!

bolbteppa

brainzzzz

Balarka Sen

@JohnRennie Bertrand Rocket's paradox

ooolb

i think the shrunk version of my new avatar suits it really

John Rennie

@BalarkaSen huh?

Balarka Sen

18:01

@bolbteppa $\infty$-category theory has propositional logic as a subset of it

Curry-Howard correspondence tfw

@JohnRennie It was a dumb joke :) You know Russel's paradox, right?

John Rennie

@BalarkaSen yes, but it didn't involve space flight last time I looked :-)

Balarka Sen

I'm missing an l

Slereah

oh hell

i soldered two pins together

probably not good

Balarka Sen

@JohnRennie The closely related statement is Barber's paradox, which asks who shaves the barber

John Rennie

@Slereah use a bit of clean wire to mop up the excess solder

Balarka Sen

18:03

My pun was a very intricate one which failed anyhow, as you see...

bolbteppa

How many 'primitive notions' do you need in category theory, this set of notes arxiv.org/abs/1212.6543 defines a set, a function, and composition of functions as primitive notions, but set theory gets a function from a relation and composition from this etc

Balarka Sen

@bolbteppa Categories are the primitive notions. That's the point.

You can have a set theoretical foundation for category theory, anyhow

user228700

G'night, folks!

Balarka Sen

But you're definitely flipped once you get to $\infty$-categories

Wayyyyy too many coherence axioms to deal with there

People usually build various models to define them

One of the possible models is "A topological space" :P

skullpatrol

cya

Balarka Sen

18:07

bye @Kaumudi

John Rennie

@Kaumudi.H Goodnight. Ping me when you want to do the Linux install.

(don't tell Bernardo we are installing Ubuntu :-)

user228700

:-) OK!

Balarka Sen

"Ubuntu? I'm going to learn Ubuntu?" - Neo

Anonymous

@BalarkaSen So I asked them about the Euler's number thing. They said that it was indeed wrong to call it a concept from mathematics' Topology. They were actually trying to find an underlying invariance factor. $(d\chi/dp)$ is close, but not quite an invariant

ooolb

@JohnRennie how long can you leave a regular piece of cheese outside the fridge for?

Balarka Sen

18:08

@Blue Ahh that explains it

Thanks!

ooolb

i bought some last night and forgot to put it in the fridge and went to sleep

is it dead

Lozansky

Is it most sensible to define the work done ON a system be a retarding moment as negative?

Anonymous

The problem now is: I need to figure out an invariant for the system :P

John Rennie

@ooolb As long as you want. Cheese doesn't go off.

Balarka Sen

Want to tell me how $d\chi/dp$ is an almost-invariant?

John Rennie

18:09

@ooolb At worst it will get mouldy, but if it's blue cheese it's already mouldy :-)

Anonymous

@BalarkaSen Yeah, I'm showing...one min

ooolb

alright i'll keep it

Balarka Sen

@ooolb you clicked the thing i linked u

you will like it

John Rennie

@ooolb You can keep cheese indefinitely at room temperature. It will continue to mature and eventually develop a rancid flavour, but it's still safe to eat.

ooolb

@BalarkaSen oh i forgot

0celo7

18:11

@Blue lmao

Balarka Sen

@ooolb I'm getting mind blown as I proceed further through the presentation

0celo7

@JohnRennie Hmm. So when cheddar gets fuzzy you can still eat it?

ooolb

reading now

John Rennie

@Lozansky in that situation we would normally say the system is doing work i.e. the energy of system decreases by the amount of work it does.

enumaris

rancid flavor...

John Rennie

18:12

@0celo7 I would be cautious if the cheese has gone mouldy.

ooolb

@BalarkaSen i know this dude

John Rennie

Fungi have some ... erm ... interesting metabolites

Balarka Sen

wait, which dude?

John Rennie

Missing comma?

Lozansky

@JohnRennie Right, thank you

Balarka Sen

18:14

Ah, that'd explain it

ooolb

@BalarkaSen no i thought i knew him

wrong dude

Balarka Sen

So you know about the presentation?

ooolb

no

the dude in the 5th slide

reich

Balarka Sen

Oh

Reich is brilliant, yes

I love Reich

r/nocontext

Anonymous

ooolb

18:14

there is something called quarter tone music i listened to before

is this what it's getting to?

Balarka Sen

Well it's about generative musics in general

Anonymous

So, uh. For the left of maximum you see it is invariant

ooolb

true

Anonymous

And for for the red line it is invariant for most of the region

ooolb

@BalarkaSen HOW DO I GO BACK

Balarka Sen

18:16

Eno is also fantastic and my favorite

Anonymous

I guess they are considering it part-wise

Balarka Sen

@ooolb no idea

Anonymous

And trying to fit it to a power law

Balarka Sen

@Blue What are they plotting $d\chi/dp$ over?

Anonymous

$|p-p_{c1}|$ and $|p-p_{c2}|$. Where $p_{c1}$ is the first critical point's probability and $p_{c2}$ is the second critical point's probability.

Anonymous

18:19

The first critical point is when lakes start to form within the white sea

Balarka Sen

Straaange

ooolb

@BalarkaSen wait a min though

did it explain why it doesn't sound random

Anonymous

And the second critical point is when the black clusters separate to form one single black cluster

Anonymous

@BalarkaSen Yeah, I'm finding it strange too

Balarka Sen

Why would one plot $\chi'_p$ over that?

Anonymous

18:20

They said they're trying to relate it which critical point for magnetization

Balarka Sen

Also what the hecker does it even mean. $\chi$ is a step function

It's not differentiable!

Anonymous

@BalarkaSen That's not true

Anonymous

Let me show you the graph

Slereah

I think I'm getting the handle on the solder

Balarka Sen

@ooolb So the mechanism is that they're playing various slices of repeated audio with a phase difference between them

It's not clear to me why we find it aesthetically pleasing

Anonymous

18:22

Balarka Sen

I don't think most people would?

ooolb

@BalarkaSen same

Balarka Sen

Lots of people hate Phillip Glass

ooolb

normally if you just think of

playing something randomly

Anonymous

See the graph on the left bottom

ooolb

18:22

it won't sound good on average

Balarka Sen

right

@Blue It is a step function. $\chi(p)$ is always an integer, isn't it? It's an integer minus an integer

Lozansky

@BalarkaSen Mind looking at the question I posed on the math chat?

Balarka Sen

"number of islands" is an integer

ooolb

@BalarkaSen this isn't random though

i don't think

like eno's trope

of course it sounds good

he knows what he's doing

Balarka Sen

Yeah I agree, it's not just making up a random schtick

There's subtle choices for the loop lengths

and phase differences

And the notes played

that are involved

@Lozansky Having a look

Lozansky

18:25

@BalarkaSen Thanks!

ooolb

@BalarkaSen did i miss the point completely?

GPhys

we had a real scalar field coupled to fermions @Slereah

ooolb

what's so special about this

GPhys

except for that I used that $Tr[1]=1$ instead of 4 on the mass term and calculated the wrong scattering cross section as a result, I think I did everything fine

Anonymous

@BalarkaSen I see your point. I think they're plotting the integer points, and then scaling it down to between $0.1$ and $-0.1$. So it resembles that graph. $d\chi/dp$ is probably the local slope or something i.e. $\frac{\Delta \chi}{\Delta p}$

Anonymous

18:28

They used bad notation...

Anonymous

You can see that the graph is not a continuous one

Balarka Sen

@ooolb It's generative. Once you start the system, it's not in your control anymore

The irrational phase difference are going to take your far far away

That's why it's not repetitive

ooolb

yeah but that's so special about them

couldn't it be anything

Balarka Sen

A piece of recorded music can't be

generative

Emilio Pisanty

@Phase See, this is roughly what I meant. It's been a long time since xkcd's put out anything this punchy.

Anonymous

18:30

The aim is however to study the relation between percolation in such 2D systems and percolation during magentization or other physical phenomena like crack formation

Balarka Sen

am I misunderstanding your question?

ooolb

probably

let me rephrase

Balarka Sen

@Blue I see, so you're smoothening the $\chi$ somehow

Anonymous

@BalarkaSen You learnt about critical point and curie temperature in magnetization, isn't it? There you must have seen the formula $\chi \propto \frac{1}{(T-T_c)^{\gamma}}$

Anonymous

They were trying to relate it to that

Anonymous

18:35

I don't completely understand it yet though

Balarka Sen

Why are these related? Their context is percolation, right?

Oh, you explained it two sentences above

@Blue Interesting!

Anonymous

@BalarkaSen Percolation explains the phenomenon of magnetization

Balarka Sen

Ahhh

Anonymous

I need to read more about this. Anyhow, looks interesting. The main author wasn't there so I couldn't get all my confusions cleared

Anonymous

I'll let you know if I find any more interesting math related to this

0celo7

18:37

@JohnRennie second round of Jambalaya 2nd edition gyazo.com/48d4bbfa8c9940e58811f8b7f10209db

Balarka Sen

@Blue Definitely do!

@ooolb In like slide 25 or so they show you a program which plays music based on the real time tram routes on Helsinski

That's pretty random dawg

But I am still listening to it

It's very beautiful

:P

ooolb

@BalarkaSen yeah it is

but is there anything special about it?

i am failing to see it

Balarka Sen

I think that's a pretentious question. The right question should be: Do you enjoy it or do you not?

ooolb

is it just abusing what humans find sounds pleasing?

i do

Balarka Sen

Then it is special, miraculously!

It shouldn't be

ooolb

18:39

if you're going to put it that way then everything is special

Balarka Sen

The point is musical grammar is a reductive way to generate aesthetically pleasing music

That's the thing these guys exploited in the 50's-90's

@ooolb Yes, the point is nothing is inherently special.

We, humans, make it so

ooolb

i know.

the question i asked before wa s

Balarka Sen

It's disappointing? :)

ooolb

is there a different way to generate generative music?

Balarka Sen

I feel ya

ooolb

18:41

lol

i'm not talking about the music

i mean the generative methods

are they special?

Balarka Sen

@ooolb Hm. Well, the fundamental idea seems to be involved in randomness.

In literature, for example

There's the cut-up technique

You cut up pages of what you wrote, arrange and glue them randomly

to make new pieces of literature, poems, whatever

This makes surprising connections between uncorrelated ideas

which in turns is what counts as aesthetically pleasing

ooolb

that's different because in the case of cut up they're glued together

the music though isn't but still sounds good

Slereah

the Sopranos have that delightful 90's charm

Nothing but terrible computers

GPhys

@Slereah in the exam the first thing I saw was $\mathcal{L}=i\bar{\psi}\gamma^\mu\partial_\mu\psi-m\bar{\psi}\psi+\partial_\mu \phi\partial^\mu\phi-\frac{M^2}{2}\phi^2-g\phi\bar{\psi}\psi$

Balarka Sen

@ooolb I guess I see your point

Slereah

18:44

The old scalar QED

GPhys

and then it asked to commute CoM decay rate of $\phi$ to two fermions

ooolb

so i guess you could generate generative music using any system with non-repetitive (but could possibly repeat) evolution.

Slereah

Commute? So how much driving

ooolb

the whole phase difference thing is just one way of doing it

and that's what i was saying

GPhys

and then it said to replace $g\phi\bar{\psi}\psi$ with $g_5\phi\bar{\psi}\gamma_5\psi$, and do it again

ooolb

18:46

it's not particularly special to generative music to have the phase difference

that's just one type ofit

is that wrong?

@BalarkaSen did you see the drum machine

it has no phase difference... right?

Balarka Sen

Yeah no I think you're right

GPhys

@Slereah meant compute*, and spin-summed as well

ooolb

but it still sounds generative and aesthetically pleasing

Balarka Sen

@ooolb True

GPhys

I computed it wrong, because I used Tr[1]=1 instead of 4 like an idiot, but otherwise I did it correct

ooolb

18:47

@BalarkaSen thanks xd

Anonymous

@CooperCape I just found something awesome: youtube.com/playlist?list=PLGAnmvB9m7zOBVCZBUUmSinFV0wEir2Vw :D (by the man himself)

Balarka Sen

It adds some stochastic noises to the base rythm

ooolb

@BalarkaSen that's kind of like glue? right?

Balarka Sen

@ooolb Oh, I didn't think badly of you. I ask myself that pretentious question everyday but try to contradict it

ooolb

ignore that

i know same

though that wasn't my intention

just said it in a bad way at first

did not get my real point across

Balarka Sen

18:49

You're fine dawg

GPhys

I deserve it for writing "m" instead of "mI", thinking I would never forget the I

vzn

@oolb hi curious are you a student? what country?

ooolb

who's oolb

vzn

sigh ~~oolb~~ ooolb

ooolb

math/phys at ut

@BalarkaSen proof?

i actually don't see this and i'm trying really hard

did it say it in the presentation?

Balarka Sen

18:51

"But the conceptual layer is significant. The idea that you're listening to the city's nervous system changes the way you experience the music." hahaha this is so pretentious i love it

@ooolb Yeah the page was linked as \stochasticdrumbeats

So I guessed that must be the case

vzn

@ooolb ut? univ tennessee? 0celo7 cohort?

ooolb

well i probably don't even know how stochastic drums sound so i'll be quiet

@vzn nah toronto

Balarka Sen

I'm not too well versed in probability theory so I have a superficial knowledge stochastic variables too

ooolb

i'm generating new patterns until i get a breakcore beat

vzn

@ooolb cool home of hinton etc web.cs.toronto.edu

ooolb

18:54

yeah

i never see him though

Balarka Sen

lol

ooolb

he's like a ghost

you'd think walking by and inside the building where his office is in like 500 times i'd see him AT LEAST once

vzn

lol busy dude, changing the world nytimes.com/2017/06/23/world/canada/…

ooolb

@BalarkaSen i found one

just need to increase the bpm to turn it into breakcore

and i just closed the tab trying to close a different tab awesome

Balarka Sen

Uggghhhh

I wanted to hear it

I'm loving the music mouse

ooolb

18:59

oh

@BalarkaSen if you click the source code

you can increase the tempo and other stuff too

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