#serious-discussion

1 messages · Page 347 of 1

deep mango
#

but i would never buy garden pizza on purpose

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Ew

snow ice
#

oh yo same, except I eat it with the soil!

deep mango
#

Likeeee

timid bronze
#

Margherita pizza is so bomb though

silent junco
timid bronze
#

Wait is there an Italian food ranking tierlist

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Lemme do it

deep mango
#

What im making is margherita

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Idk never seen that

neat lintel
silent junco
deep mango
neat lintel
#

Oh its a on pizza?

#

alr then i agree

deep mango
#

YES look at the other stuff

snow ice
#

margeritta pizza is the goat

neat lintel
limber thunder
#

at least I agree with the SSS picks

deep mango
#

I have a billion food tierlists

limber thunder
#

pesto is goated

neat lintel
#

ngl tomatoes could be a bit higher

snow ice
#

@deep mango nice hs chem test btw

timid bronze
#

Ermmm idk the rest

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Wait I lied

silent junco
#

ugh im so full i cant think about food rn

snow ice
#

im def getting blocked

deep mango
#

@timid bronze im gonna do this

deep mango
#

🤣

#

yikes

neat lintel
#

hol up imma also do it cus why not

snow ice
#

when do I stop becoming a peasant and underling and I can post images?

silent junco
#

icl zohrans fake smile creeps me out

deep mango
silent junco
#

he has a very "hello fellow kids" media presence

snow ice
#

who does?

silent junco
#

zohran

snow ice
#

ah

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don't know him

silent junco
#

nyc mayor

deep mango
#

apparently we dont have a pizza cutter here

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so ill have to use scissors

snow ice
#

he looks goofy

silent junco
#

not a knife?

deep mango
neat lintel
deep mango
deep mango
silent junco
neat lintel
#

nope

snow ice
#

I cut pizza with scissors

silent junco
#

dude

deep mango
#

Woah. Wild

neat lintel
#

Who cuts PIZZA with SCISSORS like PAPER

deep mango
snow ice
#

or nvm

#

forget what I just said

neat lintel
#

still using a knife is better

silent junco
neat lintel
#

more accuracy

snow ice
jagged forge
snow ice
jagged forge
#

interesting

snow ice
#

I should have said that I'm afraid of everyone here

jagged forge
#

boo

silent junco
#

goat cheese is disgusting

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cheese in general is gross

snow ice
deep mango
jagged forge
snow ice
#

everyone is scary

timid bronze
#

@deep mango

timid bronze
jagged forge
timid bronze
snow ice
timid bronze
deep mango
magic python
#

I can't stand most cheap cheeses tbh

snow ice
silent junco
timid bronze
magic python
silent junco
timid bronze
#

MELTED CHEESE IN PASTA CAN BE GOOD

snow ice
silent junco
#

im just saying melted cheese is better than the alternative

magic python
#

True

snow ice
#

but very cheap and is synthetic

silent junco
#

sliced cheese is revolting

timid bronze
#

Depends on the cheese

silent junco
magic python
#

I just cannot stand cold cheese (the block or preshredded bs)

timid bronze
#

I could eat gouda and pepper jack cheese straight up

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Rest no

timid bronze
limber thunder
#

lasaga

silent junco
snow ice
#

lasagna is literally just a fattener, nothing else

latent edge
snow ice
#

any other pasta is better

timid bronze
#

I'm not a huge lasagna fan but I want to try lasagna soup

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It's so popular

snow ice
#

I've tried lasgna but not lasgna soup yet

latent edge
timid bronze
#

I do love myself some pesto

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Pesto is bomb

snow ice
latent edge
snow ice
#

its good at everything

limber thunder
#

lasagna soup seems like lasagna but in a ton of tomato paste

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idk it existed

silent junco
timid bronze
#

A lot of places make it with pork 😭

snow ice
#

I for whatever reason don't get the obssession of miku and teto, I have no idea why

timid bronze
#

So I have to make tht myself too

limber thunder
#

albondiga to me isn't a soup bleakkekw

timid bronze
#

Oh rlly

limber thunder
#

it's the spanish word for meatballs

snow ice
#

Spaghetti all'assassina is my favorite type of pasta tho

timid bronze
limber thunder
#

no prob

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there's probably some soup that's based in these

latent edge
timid bronze
#

BUT I haven't yet

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I hope it impresses me

silent junco
#

im feeling sleepy

snow ice
timid bronze
latent edge
deep mango
#

Oops didnt mean for caps to be on

snow ice
silent junco
silent junco
latent edge
timid bronze
silent junco
#

indeed

timid bronze
#

Sleeping at 8 pm nawt baddd

silent junco
latent edge
#

no worries

vast wraith
latent edge
#

Real

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This too

vast wraith
deep mango
latent edge
#

True

timid bronze
#

I hate it when I'm having a nightmare or dream tht I wanna finish but then I get rudely interrupted

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Like last night I had a bad fucking unfinished nightmare

old oak
timid bronze
#

But then I got interrupted by the cold air ;-;

silent junco
#

reze arc was so good

timid bronze
old oak
#

How do you even milk hoaxes?

silent junco
silent junco
jagged forge
timid bronze
jagged forge
#

i love this sticker

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if only it was aki

latent edge
snow ice
#

everyone is scary here, Idk why

silent junco
#

like aki is lowkey kinda weak and thats what makes him cool

timid bronze
snow ice
ocean harbor
timid bronze
#

._.

latent edge
gritty heath
#

Eventually you'll be the horror too

snow ice
# latent edge I'm not :3

oh you are the complete opposite of what you think you are, your parents should've tought you better

magic python
#

Am I scary >~<

jagged forge
snow ice
timid bronze
#

Yay

snow ice
#

ur cool

jagged forge
#

also he’s so real

timid bronze
#

suremark is lowkey really scary

timid bronze
#

He gets angry very easily

silent junco
#

suremark has the patience of a saint

timid bronze
#

And he's rude to kids

snow ice
magic python
#

Nuh uh

jagged forge
#

roar

timid bronze
silent junco
snow ice
snow ice
latent edge
silent junco
latent edge
timid bronze
#

bunker made me ragequit from life

snow ice
ocean harbor
#

real

snow ice
latent edge
#

I don't get it button

vast wraith
snow ice
silent junco
#

they should make more pills bubblegum pink

snow ice
#

for short

vast wraith
silent junco
#

and other fun colors

snow ice
#

you are very scary to me

limber thunder
#

i just lurk bunker

silent junco
limber thunder
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like i lurk a ton of other places

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the loorker

timid bronze
snow ice
timid bronze
#

Then was like nope

vast wraith
silent junco
fresh comet
snow ice
#

oh send it thru dms if you want

fresh comet
#

both getting more nightmares and getting them interrupted

silent junco
snow ice
#

alright

fresh comet
timid bronze
#

higher! is not scary

snow ice
timid bronze
#

Higher is definitely scary though

latent edge
timid bronze
#

"Higher" gives doxxer vibes

random whale
random whale
snow ice
#

I hope they don't pin the message I sent

silent junco
#

higher is chill

timid bronze
fresh comet
random whale
timid bronze
snow ice
#

higher! is goated

timid bronze
jagged forge
#

BOOT = ING = higher

random whale
#

And you told the joke using...?

vast wraith
timid bronze
fresh comet
# timid bronze Nooo

it's alright EB_JolteonGiggle2
I hope your nightmares aren't the product of stressors within your life right now :c

jagged forge
#

im shocked i still haven’t gotten vactive back yet

silent junco
#

wait lemme check something

latent edge
fresh comet
timid bronze
random whale
# latent edge

Have a 5h energy instead like a true red-blooded patriot

fresh comet
snow ice
#

WHY THE F**K IS MICHEAL JACKSON LYRICS GOING ON IN THE CHAT WHILE IM PLAYING RAINBOW SIX SEIGE

latent edge
#

brb

jagged forge
snow ice
timid bronze
#

(It was too difficult I couldn't grasp)

snow ice
#

nothing too hard will happen

timid bronze
#

Oo

snow ice
#

slang is so odd rn I don't get it

silent junco
# jagged forge im shocked i still haven’t gotten vactive back yet

okay yeah im technically not supposed to be telling you this but youre blacklisted from vactive for the time being because the bot thinks youre a bot. its a new feature that we're testing out where the bot is trained to detect suspicious activity and prevents certain accounts from getting active. since the rule for going from no role to active is the same rule for going from emeritus to very active, it applies to members like you too. ill probably get around to making a pull request adjusting its behavior for emeritus members soon.

timid bronze
snow ice
#

oh

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sorry

timid bronze
#

Nws

timid bronze
silent junco
jagged forge
#

ur capping

silent junco
#

what 😭

jagged forge
#

r u pulling my leg

silent junco
latent edge
timid bronze
timid bronze
#

I thougth you were jk'ing 😭

vast wraith
silent junco
latent edge
snow ice
#

like does the bot detect it if you are spamming a bunch of the same message

vast wraith
#

i still havent at all gotten to look at adic stuffs breadpensive

silent junco
timid bronze
latent edge
#

ok then dw let me delete

jagged forge
#

i was scrolling for like 5 minutes bro

silent junco
#

LMFAOO

timid bronze
#

LMFAO

snow ice
#

LMFAO

latent edge
snow ice
#

I'm so glad Super Matroid doesn't know who I rly am

jagged forge
vast wraith
snow ice
timid bronze
latent edge
snow ice
#

I see it

latent edge
#

Essentially what you do is use Kronecker Weber

silent junco
jagged forge
timid bronze
latent edge
#

Well I forgot to say (abelian) number fields over Q

jagged forge
#

stupid autocorrect

latent edge
#

In general it's not so easy

timid bronze
#

Do I need to set you up a spherical integral

jagged forge
snow ice
#

rn I'm just sitting in the event stage doing literally nothing lol

timid bronze
jagged forge
#

this is a powerful egg phobia

vast wraith
latent edge
#

Every abelian number field over Q can be seen in a cyclotomic extension

snow ice
#

I'm just bored @timid bronze

latent edge
#

Then the next step is the isomorphism between the Galois group of the cyclotomic extension and (Z/mZ)^x

#

from there you can consider characters from (Z/mZ)^x -> C^x

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Now from the theorem above you essentially identify the abelian extensions with some subgroup of this guy

#

For example take Q(zeta_8)/Q

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consider the character given by chi(1)=1, chi(3)=-1,chi(5)=-1 and finally chi(7)=1

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Then you look at the kernel of such a character

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In this case it's {1,7}

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Now you look at the fixed field of this

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7 corresponds to sigma_7 which is complex conjugation

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This tells you that the field is real

snow ice
#

where's mi ipad

latent edge
#

and quadratic

snow ice
#

NO where's mi ipad

timid bronze
latent edge
#

since phi(8)/2 = 4/2 = 2

snow ice
#

I see

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I'm listening rn

latent edge
#

With some effort you can check that the field is Q(sqrt(2))

vast wraith
#

lovely

latent edge
#

yeah that's field theory and some fancy character theory so far

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okay now you might ask where is the number theory

snow ice
#

I see

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I understood it

latent edge
#

Okay so a classic question you can ask given a number field K is classify its primes

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Given a prime p over Q how does it change when you look at this number field K over Q

vast wraith
latent edge
#

uhh what do you mean by this

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class numbers tell you if the ring of integer is UFD or not

snow ice
latent edge
#

measures the failure of UFDness

latent edge
vast wraith
latent edge
#

The idea the original isomorphism we had earlier

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Galois group of zeta_n over Q

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the isomorphism is given by sigma_k: zeta_n -> zeta^k_n right

snow ice
#

assuming

latent edge
#

you have to elaborate on that

snow ice
#

where in K=Q(a), a has minimal polynomial f(x) that is an element of Z[x]

latent edge
#

not exactly

snow ice
latent edge
#

the issue is you don't know the ring of integer beforehand

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so this might tell you false info when you take modulo p

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Good thing is it works for almost all primes

snow ice
#

I see, it only works for most primes, those dividing the discriminant.

latent edge
#

yup

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but what I'm showing is another way to get the same info

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Let's take an easier example for demonstration

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Take Q(zeta_4)/Q = Q(i)/Q

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From earlier discussion this has Galois group isomorphic to (Z/4Z)^x

snow ice
#

mmhmm

latent edge
#

okay now let's look at Dirichlet characters

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(Z/4Z)^x has 2 elements so we should also expect 2 characters

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One of which is the trivial character and the other is quadratic in nature

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Given by chi(1)=1, chi(3)=-1

snow ice
#

yep

latent edge
#

Yeah now the golden key is realizing that from the isomorphism you can relate Frob_p in Gal(Q(i)/Q) with p

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so chi(Frob_p) = chi(p) for unramified p

snow ice
#

OHHH

latent edge
#

now we look back

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for primes p = 1 mod 4

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plug in the formula

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you get chi(Frob_p) = ?

snow ice
#

chi(Frob_p) = 1?

latent edge
#

yes

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what does this tell you?

snow ice
#

P splits in Q(i)

latent edge
#

right

#

how about p = 3 mod 4?

snow ice
#

-1?

latent edge
#

yeah and what does that correspond to?

snow ice
#

p is inert in Q(i)

latent edge
#

mhm

#

now the only missing thing here is p=2

snow ice
#

:)

latent edge
#

you can check this one is ramified

latent edge
snow ice
latent edge
#

there's also a result to keep in mind if you get chi(p)=0 this tells you that p is unramified

#

and sure enough 2 is not coprime with 4 as you mentioned so there we have it

snow ice
#

got it

#

its fun learning with a post-grad person as a pre-uni :D

latent edge
#

yeah you can do similar things with more complicated examples as long as you are working over Q and your number field is abelian

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If your number field is not abelian then you forget about it

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You need more machinery to handle these

snow ice
latent edge
#

No I mean math tools

snow ice
#

OHH

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I think we scared @timid bronze away lol

latent edge
#

Anyways

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You might wonder what if we don't work over Q

snow ice
#

i quite do

latent edge
#

Just any arbitrary number field K and keeping stuff abelian

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yeah for this the answer is not far off from the story over Q

snow ice
#

oh

#

I see

latent edge
#

yeah but it requires more care to get the right arithmetic object

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Essentially you want to play the same game. Over Q we had (Z/mZ)^x and so the task is to somehow generalize this group

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So that it works for our needs

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I will not get into the details cuz it might be too much lmao

#

But essentially that's what you do in class field theory

snow ice
#

I got it

#

tysm

latent edge
snow ice
#

@timid bronze YOU CAN COME BACK NOW! WE ARE DONE WITH OUR BEAUTIFUL MATH DISSCUSSION!

latent edge
snow ice
#

the one made for high schoolers

latent edge
#

No I meant number theory

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not that

snow ice
#

yes

latent edge
#

Things like decomposition group and whatnot

#

what year are u in

latent edge
#

ok so you were using chatgpt?

snow ice
#

to understand a bit yes

latent edge
snow ice
#

I know sets, coprime

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elements

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and int rings

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...

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sorry

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I do know modular arithmetic too

latent edge
#

It's okay next time don't use chatgpt for mathematics

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If you don't understand what I say sometimes just let me know I can explain

snow ice
#

I understand now however

#

isomorphism

latent edge
#

Do you really understand isomorphisms

snow ice
#

the concept yes

gritty heath
#

Its just equality if you squint hard enough

latent edge
#

ok tell me what you understand

snow ice
#

its a structure-preserving translation between two objects

#

sets with the same number of elements are isomorphic

latent edge
#

Have you seen groups before?

snow ice
#

yep

#

lots of times

latent edge
#

quotient groups?

snow ice
#

nope

#

can you teach me?

latent edge
#

yes but before that I want to make sure

#

Take Z to be our set

snow ice
#

yes?

latent edge
#

and take multiplication to be our operation

snow ice
#

yes?

latent edge
#

Is this a group?

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dont use gpt

tropic pivot
snow ice
#

yes.

latent edge
#

why

timid bronze
#

But nah, I went to go do something

snow ice
#

:(

#

its not a group

latent edge
#

that's right it is not

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but say you are given one move to make it a group and that move is shrinking your set

snow ice
#

yes?

latent edge
#

Obviously if you shrink down to 1 element it is a group but that's not interesting

#

What's the largest set you can shrink Z to in order to make it a group?

snow ice
#

2 elements

#

1, -1

latent edge
#

can you check for me why is this a group?

snow ice
#

first three (closure, associativity, identity) work for all ints with mult operation

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and 1 has its inverse that's an int (1) and -1 has its inverse that's an int (-1)

latent edge
#

yep good job

#

:3

snow ice
#

:3

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is this knowledge good for a 13 year old?

latent edge
#

yeah groups are really nice

snow ice
#

:)

latent edge
#

okay consider the following thing

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say you have a butterfly

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🦋

snow ice
#

prettyyyy

#

but yes

latent edge
#

yeah now we want to classify the symmetries of this thing

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you can see that if you draw a line in half

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then you can reflect the butterfly

snow ice
#

right in the vertical middle

latent edge
#

and it still looks the same

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right

snow ice
#

yes?

latent edge
#

alright anything else?

snow ice
#

nope?

timid bronze
snow ice
timid bronze
#

Damn

snow ice
#

anyways

latent edge
#

doing nothing still preserves the shape of this butterfly

snow ice
latent edge
#

so it is a valid symmetry

snow ice
#

I see

latent edge
#

okay great let's use r to denote the reflection symmetry

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and 1 to be the "do nothing" symmetry

snow ice
#

yes?

latent edge
#

so in total we have 2 symmetries right

jaunty ibex
solar spire
#

so

#

like

#

he gotta lock in

jaunty ibex
#

ok buddy

snow ice
latent edge
#

now observe this: what happens if we do r twice?

#

you know you take your butterfly and reflect twice

snow ice
#

its no longer symettrical

latent edge
#

huh

timid bronze
solar spire
#

hes very far ahead for 13

latent edge
#

okay so say this is the butterfly (left|right)

snow ice
#

yes?

timid bronze
#

Very well then

latent edge
#

if you do one reflection what happens

snow ice
#

the right is on the left

latent edge
#

yeah you got it good job

#

now do it one more time

jaunty ibex
#

u just get back to where u are

latent edge
#

this is confusing to read

#

is it (right|left) or (left|right)?

snow ice
#

left right?

latent edge
#

yeah exactly

#

you see what happened here?

snow ice
#

I do...

latent edge
#

when you reflect twice it's the same as doing nothing

snow ice
#

oohh

latent edge
#

yeah the way you write this mathematically is like this: r^2 = 1

snow ice
#

oh

latent edge
#

where squaring here means doing twice

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1 here is the "do nothing" move

snow ice
#

I thought it would be something like x = 0 mod 2

snow ice
latent edge
#

lol this is also something similar actually we will get to that

latent edge
#

okay but here's the gist

#

in our previous group we had {1,-1}

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you verified this was a group and said 1 is the identity

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and (-1)^2 = 1

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right?

snow ice
#

yep

latent edge
#

okay now in this new group we made let's call it the "butterfly symmetry group"

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we have {1,r}

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1 is the identity

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and r^2 = 1

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right?

snow ice
#

yes.

latent edge
#

so what we conclude from this

snow ice
#

r u saying

#

r^2 is the identity?

latent edge
#

yes

snow ice
#

and the set is {r^2, r}?

latent edge
#

yeah you can write it like this if you want

snow ice
#

I see...

latent edge
#

yeah but the upshot here is that

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{1,-1} and {1,r} are the "same" group

snow ice
#

yep?

latent edge
#

same as in they have same number of elements

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and the way the 2 groups interact are identical

snow ice
#

yes.

latent edge
#

a fancy term to say they are the same in math is isomorphic

snow ice
#

mmhmm

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so that's isomorphism

latent edge
#

but you see the beauty in this?

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yeah exactly

snow ice
#

i do a lot

latent edge
#

we had 2 different ways to make the same group

snow ice
#

this is very neat

latent edge
#

one comes from number theory

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and one is just symmetries

snow ice
#

geometry and number theory intertwine 🤯

latent edge
#

yeah lmao

snow ice
#

lol

latent edge
#

okay you mentioned mod 2 arithmetic earlier

snow ice
#

yes

latent edge
#

when you take numbers and mod out 2

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the resultant is either 0 or 1 right

snow ice
#

yes

latent edge
#

okay let's look at this under addition

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basically i want to say that we can just take the elements {0,1} in this group

snow ice
#

mmhmm

latent edge
#

since anything will just collapse to these two numbers modulo 2

snow ice
#

yep

latent edge
#

okay great

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what is the identity here?

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it's either 0 or 1 so you have a 50/50 chance lmao

snow ice
#

0?

latent edge
#

yeah why

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because if you add anything to 0 you just get that number

snow ice
#

a+0 =a

latent edge
#

yeah right

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also what happens if we add 1+1 modulo 2?

snow ice
#

to what?

latent edge
#

just add 1+1 and take mod 2

snow ice
#

its 0

latent edge
#

exactly

#

we found a 3rd group with the same properties

snow ice
#

:)

latent edge
#

2 elements and one of the elements goes back to identity when you do it twice

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so this group is also isomorphic to the other two groups we discussed

snow ice
#

i see

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I really do

latent edge
#

yeah im glad

#

You can take this idea really far and do amazing stuff with it

snow ice
#

one equation is a regular one, one is from mod arithmetic, and one is a representation of geometry

snow ice
deep mango
#

@timid bronze i did it

snow ice
#

or use it?

latent edge
#

that would be abstract algebra

snow ice
#

i see

latent edge
#

if you are curious I can give you a book to read which I think is somewhat readable

snow ice
#

like linear algebra?

latent edge
latent edge
snow ice
#

I bookmarked it

#

it seems neat

latent edge
snow ice
#

I'll def read this sunday

latent edge
#

yeah have fun then

snow ice
#

tysm

#

:)

torpid bay
latent edge
#

let me teach you about cohomology of arithmetic groups

#

jk

torpid bay
#

bnuuy am scard

#

i do have a question tho

#

I was looking at functions that converge on the unit circle, like $\sum_{n=0}^{\infty}{z^{q^n}}:q\in\mathbb{Z}^{\geq2}$

fathom swallowBOT
#

Yeatte

torpid bay
#

and I saw a few symmetries in it, but I was wondering, for a function f(z), with certain 'nice' properties, I was wondering if instead of going from f(z) -> symmetries(f(z)), If its possible to go the other way? and also if it's a one to one relation

rough basalt
#

campus has reopened

#

I lurk in the physics building once more

latent edge
latent edge
#

so you are basically looking at lacunary functions

torpid bay
#

like, If I have a group (probably a certain kind of group ig given that i have the restriction of complex numbers), can I always be able to find a function f over the complex numbers where that has those symmetries? like with the sum above, f(ze^(2ipi/(q-1))e^(-2ipi/(q-1)) = f(z) as a symmetry, and f(z^)^ = f(z) as another

latent edge
#

okay okay

#

so given a g in G you are interested in functions f(g.x) = f(x)?

#

g.x here is the group action on your set

torpid bay
#

ye

latent edge
#

right then I have a lot to say about this

torpid bay
latent edge
#

let's start with easy examples

#

You can view the cosine function as an example of this

#

Do you see how?

torpid bay
#

yeppers

#

translation as an exmaple

#

cos(x+2pik) = cos(x) :integer k

latent edge
#

you can do better than translations but you are on the right track yeah

torpid bay
#

cos(x)=cos(-x)

latent edge
#

yeah there is also this guy yup

torpid bay
#

pandahmm also compelx conjugation

#

right?

latent edge
#

let's work with R for now

torpid bay
#

ok

gritty heath
#

I think complex conjugation doesnt work

timid bronze
#

Bro I’m so sad

latent edge
#

okay let's use T for translation

#

and S for reflection

#

So we have these actions on R: Tx = x+2pi and Sx = -x

#

so far so good?

torpid bay
#

yep

latent edge
#

right if you play around a bit with these

#

you can see S^2 = id here

torpid bay
#

yep

latent edge
#

and STS = ?

torpid bay
#

T^-1

#

?

latent edge
#

yup

torpid bay
#

-((-x)+2pi) = x- 2pi

latent edge
#

So this group G is generated by two elements S and T such that it satisfies the properties we discussed above

#

this G has a name and it's called the infinite dihedral group for obvious reasons if you've seen dihedral groups before

torpid bay
#

i know the finite one ye

#

the 2 element, but i hadnt heard of ones larger than that

latent edge
#

yeah the infinite guy naturally gives you the sinusoidal functions

#

you can see that one of the sinusoidal functions is invariant on the whole group

#

but one of them is only invariant under translations

torpid bay
#

the infinite one?

latent edge
#

yes we are still talking about the dihedral group

torpid bay
#

ah ok

#

ye

latent edge
#

notice that cosine is even right

torpid bay
#

yep

latent edge
#

so cos(Sx) = cos(x)

#

and obviously it is invariant under translation

#

that's the whole thing

#

meanwhile sine is odd

#

it's very common to attach a factor in front of the resultant for these cases

#

Like sine gives you a minus sign whenever you do S right

torpid bay
#

yep

viral yew
latent edge
#

so this motivates you to cook up a character chi: G -> {1,-1}

#

where it outputs 1 for T and -1 otherwise

#

Then your sine function will look like sin(g.x) = chi(g) sin(x)

#

cool right

torpid bay
#

ye

latent edge
#

yeah this POV gives you more meaning for these things

sterile bolt
#

why are people so smart

latent edge
#

I find it really fascinating

torpid bay
#

I rmemeber needed an outside thing for the lacunary thing as well pandathink

latent edge
#

yeah there we go lmao

#

we can cook up a fundamental domain for these functions

#

you already know [0,2pi] works for translations

#

but in this case we need to shrink it a bit

#

what would that be

torpid bay
#

I haven't heard of a fundamental domain, what is it?

#

is that like a minimal one or smthn?

gritty heath
#

Analysts regularly exploit symmetry to study and break down functions

#

Fourier analysis is basically that

latent edge
torpid bay
latent edge
torpid bay
#

oh I think i heard of that idea then

latent edge
#

just like how with translations the fundamental domain is [0,2pi]

#

anything will just be a copy of this guy

torpid bay
#

h

#

if I combine the S and the T, I feel like i can shrink the fundy domain quite a bit

#

[0,pi/2]?

latent edge
#

why so

#

well hold your hourses for a min let's define a fundamental domain

timid bronze
#

My parents’ relationship has gone to shit

#

All my mom can talk about rn is a divorce

#

And she has nothing good to say about my dad

latent edge
#

Take an F in X. F is a fundamental domain if it satisfies these two properties:

  1. for all x in X, there exists a g in G s.t g.x is in F
  2. If x_1,x_2 are in the interior of F and g.x_1 = x_2 for some g in G then x_1 = x_2
deep mango
timid bronze
torpid bay
#

all right, makes sense ye

#

hold up

#

interior of F

#

pandathink i see why making interior of F distinction is necessary now

latent edge
#

yeah do you see why [0,pi/2] doesnt work?

#

hint: condition 1 fails

torpid bay
#

ye it doesn cover the pi/2 to 3pi/2 part

#

I would need the cos(x+pi) = -cos(x) thing to do that, which we didn't list as our syms

#

then should we change the translation thing to this and have another chi for it?

latent edge
#

yeah if you take 3pi/4 i think then it doesnt quite work

latent edge
torpid bay
latent edge
#

yeah you'd need to change how you set your symmetries

#

you can take T to be x->x+1

#

but then you have to add some constants to make stuff work nicely right

torpid bay
#

yeah

latent edge
#

but yeah it doesn't matter what you take it is going to be the dihedral group again

torpid bay
#

yep

latent edge
#

Maybe as a fun exercise think about other examples with different groups

#

Maybe try the cyclic group with n elements or the normal dihedral group

#

see what you get

torpid bay
#

I feel like z^k would be nice

#

(ze^(2ipi/k))^k = z^k when k = 1,2,3...

#

compelx nums tho, stretching can work

#

(az)^k a^(-k) = z^k

#

a fundamental domain for that, when allowing stuff outside f(z), feels like there isn't one?

#

if we don't, then z^2 would be the normal dihedral group then i think

#

as for cyclic, just z^k = f(z) then (over the ocmplex numbers)

#

whose fundamental domain would be an infinite pizza slice from r = 0 to inf and theta from 0 to 2pi/k then? pandathink

#

,, a^{x\partial_x}f(x) = f(ax) \ a^{x\partial_x -k}(x^k) = a^{-k}(ax)^k = a^{-k+k}x^k = x^k

fathom swallowBOT
#

Yeatte

torpid bay
#

$T(f)(x) = f(x)$ where T is symmstery vs $ f(g.x) = p(g)f(x)$ such that g is symmetry pandathink

fathom swallowBOT
#

Yeatte

foggy meadow
#

So, the derivative uses a modification of the mean value theorum.

torpid bay
#

ye

foggy meadow
torpid bay
#

me trying to remember what the disc thing is...

foggy meadow
torpid bay
#

ah those, im still thinking about them, the thing in #math-discussion seems to be tantentially related

foggy meadow
#

I found it though, yay//

grand wraith
#

can someone solve this rq

#

4(2+1)/2+1

#

not division

#

a fraction

neat lintel
#

So it's 4(2+1) all over 2+1 if I'm reading it correctly?

#

@grand wraith

slow pier
ancient frost
#

i think add 1 after

neat lintel
#

So then it's (4(2+1))/2) +1 ?

slow pier
neat lintel
#

Right, I add them just to simplify it

young fern
#

U made ur account dec25th 2025

snow ice
#

I chat frequently here, I'm not an advertiser

#

I'll just delete the post if you want

young fern
#

Yea ion think u can sell stuff here. But if u deleted it it's fine.

snow ice
#

it's just funny cuz of the ram epidemic

young fern
#

Lol is there rlly

snow ice
#

anyways gn

young fern
#

Alr man gn

sonic field
#

@timid bronze don't tell me I don't season MY food...

hexed tangle
sonic field
#

u cray 🤣

real summit
#

CHROMAKOPIA

silent junco
#

true

#

i only learned it for normed vector spaces but i guess you can weaken the condition and the proof holds yeah

delicate plover
#

YO. wait

#

I cant do simple arithmatics now

brave flare
hot lion
#

topological vector space mfs coming up with 45 adjectives for their spaces instead of just studying banach spaces like normal people

hexed tangle
#

LMAO

cyan karma
#

Like memorization

#

You may think they are funny but they merely evolved in a different direction

silent junco
#

why dont they just start naming their spaces by the axioms themselves

#

like T_n spaces

brave flare
#

i dont think T_n spaces are a good example of naming scheme

old oak
brave flare
#

me when regular vs regular hausdorff

#

which one is T_3? noone knows

old oak
#

The worst part is that according to this, the Arens-Fort space is a perfectly normal topological space

old oak
#

Well, the T_0 and T_1 ones aren't Hausdorff, but you know what I mean

#

I wonder who even studies T_0 spaces specifically? The T_1 class at least has the Zariski topology as a representative that's actually used.

brave flare
#

i dont think i even know rn what T_0 is

#

isnt T_1 that {x} is always closed

old oak
#

T_1 is "given any two points, each of them has a neighbhorhood not containing the other", and is equivalent to singletons being closed

old oak
#

T_2/Hausdorff is "any two distinct points have disjoint neigborhoods" and is the only separation property worth remembering unless you're some kind of sicko

#

(and yes, I am some kind of sicko)

zealous bronze
#

specifically when not every prime ideal is maximal

sonic field
hexed tangle
#

in Spec R a point is closed iff the prime is maximal most primes aren’t so their closures contain larger primes singletons fail to be closed hence the Zariski topology is typically not T_1

old oak
sonic field
#

I kinda felt that way too. Ok

old oak
#

most of them don't come up very often anywhere, other than Hausdorff.

hexed tangle
hexed tangle
#

honourable for a reason

sonic field
old oak
#

So the other separation axioms are sort of intended to give you a substitute for the kind of things you'd easily get out of metrizability.

#

(the Urysohn Lemma being a big example)

#

So that basically means they come up in niche situations suited to a particular kind of spaces studied in a particular kind of area (and topological methods come up in a lot of areas)

hot lion
#

the next big thing after Hausdorff is normality/T4 id say

old oak
#

Fair

hot lion
#

Because of the significance of urysohns lemma

#

Oh yeah you mentioned that

hexed tangle
#

indeed

sonic field
#

I guess it's not surprising that at some point it would emerge from anything in number theory... Not that I know much about it.

Then I read how generating functions can be used to construct a topological space. But then I guess that's more algebraic anyway.

-sigh-

#

It reminds me a little of this talk I went to years ago by one of my old profs, I forget wtf she was doin maybe I can find the paper. But she used some sort of stacking technique with higher dimensional structures to also create manifolds. Her jam was fibrations (omg phone stop). There's so much topology to learn ._.

jagged forge
sonic field
#

Now that I think about it, feels like the type of manifolds she was carving out was something similar to the grassmannian

#

... The more I think about it, the more that .makes sense...

#

Ugh y I doin this early in the morning. I want pancakes

sonic field
#

Yeah it was nuts it's like she took slices or something from a number of hypercubes and when she stacked them a particular way it created some sort of manifold structure. I could be very wrong tho, this was back in like 2912

#

2012 LOL

#

I'm so cooked

hexed tangle
#

will help ya focus better

sonic field
#

Fr lemme do that.

#

🌪️

timid bronze
timid bronze
# sonic field

@solar hawk You’re allergic to all of this

@jagged forge Am I right

solar hawk
#

Something*

#

How come there’s no slowmode in discussy 2?

old oak
#

6 hours or thereabouts

timid bronze
hexed tangle
timid bronze
#

Also why am I a FISH

#

Are you calling me boring

hexed tangle
solar hawk
#

Fish

hexed tangle
#

who can swim through the vast ocean

timid bronze
#

I feel like you’re tying this to a negative connotation.

#

I know your antics.

solar hawk
#

Crazy work

hexed tangle
#

i'm just being kind

timid bronze
#

Mhm…

solar hawk
#

LMAO

timid bronze
solar hawk
#

Why

#

Why would anyone do such a thing

timid bronze
solar hawk
#

Oh

#

It tastes like a muffin??

#

Then yea

#

Ez healthy muffin

timid bronze
#

You need to get your vegetables in someway or another

#

Since you hate veggies

solar hawk
#

I could just eat one of those

#

Veggie smoothies Suremark said

#

But he said it’s as

#

Ass

timid bronze
#

I can confirm veggie smoothies are ass

#

Especially celery ones

#

Veggies are so good

#

Idk how kids don’t like them.

solar hawk
#

Bro

#

I like some veggies

#

Like

#

Broccoli, zucchini

jagged forge
jagged forge
jagged forge
timid bronze
#

They’re bomb

jagged forge
#

zucchini noodles? don’t think i’ve heard of that

#

actually i feel like that’s something jay would make

silent junco
#

zucchini noodles sounds like it shouldnt work but it does

solar hawk
#

Egg drop soup

timid bronze
#

I have it with pesto

#

And

#

Charred cherry tomatoes on top

silent junco
#

ooh

#

yes

deep mango
timid bronze
jagged forge
#

i think jay made it before actually now that i read chat logs lol

#

that looks awesome

timid bronze
#

So like a tiny bit burnt

jagged forge
#

i had pad thai with konjac noodles last week but i think the noodles were overcooked cuz they were mushy sadly…