#serious-discussion
1 messages · Page 475 of 1
mniip
the squaring part is obviously easy, the fun part is in the addition
$$ae^{ib} + ce^{id} = \sqrt{a^2 + c^2 + 2ac\cos(d-b)}e^{i<atan2>(c \sin(d-b), a + c\cos(d-b))}$$
mniip
so we get
$$e^{p+ib} + e^{q+id} = e^{\log\left(\sqrt{e^{2p} + e^{2q} + 2e^{p+q}\cos(d-b)}\right) + i<atan2>(e^q \sin(d-b), e^p + e^q\cos(d-b))}$$
mniip
now here we get to branch on p < q or p > q
well if p >> q these expressions are going to be inaccurate
$$\log\left(\sqrt{e^{2p} + e^{2q} + 2e^{p+q}\cos(d-b)\right) =$$ $$=\begin{cases} p + \frac{1}{2}\log\left(1 + e^{2q - 2p} + 2e^{q-p}\cos(d-b)\right) & ,p \ge q \ q + \frac{1}{2}\log\left(1 + e^{2p - 2q} + 2e^{p-q}\cos(d-b)\right) & ,p \le q \end{cases}$$
mniip
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idk where the error is
but yea, this is really good because the e is always taken to a negative power
serving as a correction to 1
that's clever
you can do that same for the atan2 part
god I remember trying to do optimizations like this to my holomorphic dynamics plotter I wrote years ago

just use mpf
I feel intellectually outpaced in this discord chat.
I mean it was a programming class project so I did everything from scratch in C++

yea bignum arithmetic is one thing I know not to do by hand
libgmp is just too good
Anyone took analysis here?
does this remind anyone else of a fruit lolly
sigh
I understand type 4 functions but I don't understand the coordinate system it uses 
i tried googling type 4 function and all the results are about type 4 collagen, so i can't help you


ok it's pretty stupid
Literally what is this
I’m trying to think of a set that could possibly satisfy these conditions
for all x in A, x and A are disjoint
for all x, y where x ≠ y, then x is in y or vice versa
if x is in y and y is in A, then x is in A
the natural numbers are a good example of this, suitably constructed
@vivid halo where I can get 10th class solutions?
What suitable construction
ok I made a better and more compact mandelbrot in latex
all von neumann naturals satisfy this condition
so does the set of all von neuman naturals
But 2 intersect 1 = {Ø, {Ø}} intersect {Ø} = Ø right? I feel like I’m being like super dumb rn
{Ø, {Ø}} intersect {Ø} is {Ø}
2 intersect 1 = 1
Oh shoot
🧠
Yeah intersect is the set of common ones
not sure what this has to do with anything though
Nah i was just testing them out a bit
yea so the naturals form the first infinite ordinal, \omega_0
each Von Neumann natural forms a finite ordinal contained in \omega_0
yea
Would it be weird to write that N = omega_0 ?
it depends on what structure you're considering
usually N refers to just the underlying set
\omega_0 refers to the underlying set along with the order relation
cardinals are sets considered up to bijection
whereas ordinals are sets along with a well order relation considered up to order preserving bijection
Are there any functions f:N -------> R that are one-to-one?
sure, the obvious inclusion
Hmm, but isn't the condition for one-to-oneness the fact that both sets have the same cardinalities?
no not at all
any inclusion is one to one
just not onto
one to one and onto means bijection and then yea in that case you need same cardinality
I think he has a definition that one to one is bijective
Both a surjection and a bijection.
I hate the terms "one to one" and "onto"
Me too
I like how they sound a little closer to their meaning, but after using the -jective words enough times, it becomes intuitive anyway
how is "onto" closer to its meaning?
You're probably thinking of "one to one correspondence". This is not the same as "one to one". I know, it's stupid.
Like you’re putting something big onto something small
this one always fucks me up. i always have to google it
When you learn that stuff for the first time, it’s just a bit easier
But it’s stupid because you confuse injection and bijection
I'm okay with both but I prefer injective/surjective/bijective over the alternatives
mono/epi/iso 
All injections are bijections into their image 
Ok so cardinals and ordinals are the same except ordinals have WO on them and the bijections preserve the WO
no?
Kinda?
cardinals are sets modulo bijection
ok wait then what is it
ordinals set well-ordered sets modulo order-preserving bijection
Oh
what in the fever dream is all this?
Yeah that's a good way of putting it mniip
I feel intellectually outpaced in this chat.
ordinals have more structure as well as a smaller quoetienting relation
So it’s like an equivalence class of all sets with the same cardinality
Though don't you need AC to get a cardinality for every set
equivalence class
Ye ye
yea that's a cardinal
vaguely
Yeah aren't cardinals well-orderable sets modulo bijection?
all sets are well-orderable 
I mean yeah
So I understand the purpose of cardinals, but why do ordinals exist
well-orderable != well ordered
Join the club
to describe transfinite processes
I mean I'm keeping up right now
Transfinite induction?
a cardinal number describes how many there is of something, an ordinal number describes when something comes up in "sequence"
But like half the time this chat talks about serious math it's just gibberish
Though it's fun to see myself gradually understanding more and more
i used to be in ur position, it’s not actually as weird as it sounds
Oh that makes sense
Because it’s got the order, right
If you spend a lot of time here you will pick up on what the big words mean until you become another one of us, people who use big words without really knowing what they mean
whenever nG posts pictures I don't understand a single symbol
That's because he just makes things up
I swear when I start learning this stuff, I'm stunting on all of you so hard.
Hmm yes. Etale cohomology. Ah yes, bundle epimorphism.
So ordinals seem like a generalization of the natural numbers (since N describes when something comes up in sequence)
how do i do this?
Ahhh yes, Aether.
yes
ordinals are for like, "longer" sequences
Category theorists just scribble arrows everywhere and call it math
Modulo requires an equivalence relation on the “set of all sets”, no?
yeah hence the actual definition is trickier
Wait can you not have equivalence relations on a class?
So it gets finicky with the axioms you’re using, I’m guessing
with choice we can actually provide a "canonical" representative for every cardinality
I don't see why you couldn't
Cause set of all sets isn’t a thing, right
you want to take the quotient
it's too large
You just define it with formulas rather than a set
Right you can't actually take modulo on V
Hence the canonical cardinals
God I find it so cool that I actually know (basic) set theory now
one way to do it is take a set X, come up with a well-ordering, which will give you an order-preserving isomorphism with some ordinal alpha, and then in alpha+1 take the least ordinal with the same cardinality as X, which is well-defined because alpha+1 is well-ordered and contains at least alpha
you can show this is independent of the choice of the well-ordering (and resp. alpha)
in this definition all cardinals are ordinals, but only very particular ones
I mean you just take the smallest cardinal with an injection into the set as its cardinality
*largest
Cardinals are just ordinals k s.t. alpha<k implies there is no injection from k into alpha
Yeah I just didn't read what you said :chad:
but also in your definition you can't take the "largest cardinal"
not well defined
Just reverse the well ordering 
Right you just take the smallest cardinal that the set can inject into
sure
wait what’s an ordinal defined as here
.
the real no. number line seems in 1st dimension only back and forth but to reach 4 th dimansion we need a 3d dimesion, my thought
So what did you mean by this then
That definition I pasted doesn’t have modulo
abstract idea vs concrete implementation
The way I saw oridnals defined is a transitive set well-ordered by set inclusion
Ok so like
The modulo is the idea
But since that’s impossible
You have to define it kinda carefully
well
there's a relation of isomorphism on the category of well orders
and the von-neumann ordinals (defined in your image) form a skeleton
meaning there's exactly one von neuman ordinal in each isomorphism class of the category of well orders
i.e. we can use the class of von neumann ordinals as an "implementation" of V/~
Ok
Do the vn ordinals act as a sort of representative for the “equivalence class” or does that not apply here
exactly
This is your brain on computer science
Ok that sort of makes sense yeah
no this is cat theory
Yeah I was gonna ask
there's a universal property you want to satisfy (quotient)
Doesn’t this have some things outside ZFC
Isn't everything you do cat theory mniip?
large categories and all that
I find a way to relate everything to cat theory
Since you're a cat and you do theory
Small cats are like, each object is a set right
no
Small cats are also cute
the collection of objects is small enough to be a set
Oh ok
you'd think basic arithmetic is safe
but alas
What’s V
L
No way
initiality in some category, usually category of cones
could be a slice category of a profunctor
You say this like you think I have any idea what those words mean
The extent of my category theory knowledge is the definitions of category and functor
Lol yeah
Is there a nice, formal implementation of ordinals and cardinals in ZFC? Or do they all rely on some weird properties to sidestep things like “set of all sets”
Yes
in vague terms, we're looking for some object with a certain pattern of arrows, such that for any other object with its own pattern of arrows, there exists a unique "mediating arrow" such that the second pattern factors through that arrow and the first pattern
Ordinals and cardinals can be formalized within ZFC. If they couldn't, ZFC would be kinda lame
Sounds like a morphism of morphisms in a sense
Or like, a morphism between entire categories
no
So... a functor
yes there is
the "set of all sets" is mostly there for intuition
mniip how should I learn cat theory
you can do the rigorous details
Like how much should I be learning for alg top
up to you
for "normal maths" it's useful to learn at least the "categorical language", i.e. the definitions of initial objects, products, equalizers, pullbacks, their duals; as well as the notion of functoriality and naturality
Category theory is completely formalized right? Like ZFC?
uhh
category theory is more of a vibe in that it extends beyond ZFC
but if you insist you can formalize category theory inside ZFC
but there will be caveats
is Riehl's book good for intro cat theory
I guess
Well take the “category of sets”, for instance, how is that formalized
Like are categories undefined objects sorta like sets and you define their properties
you take a universum U and take the category of elements of U
a category whose set of objects is in U is called U-small
if C is U-small then [C, C] might not be U-small anymore
Hold up, what’s a universum, and you said take the category of elements of U
But what is a category (formally)
if we're restricting our attention to ZFC, it's a set Ob, together with a family of sets Hom(X, Y) where X, Y range over Ob
together with a family of elements id_X in Hom(X, X) for every X in Ob, and a family of functions \circ : Hom(Y, Z) x Hom(X, Y) -> Hom(X, Z)
that satisfy some identity and associativity conditions
Yep
the "categorical vibe" implies that Ob doesn't have to be a set and can be something more vague, like a class, or something without a notion of equality at all
people talking about size issues
ng has joined the chat
for Hom we actually care about equality
I love this, categorical vibe
but it can still happen to be a class
If it’s not a set, then what is it? Lol
That’s what I’m asking
it can be taken to be a proper class
no that's not what you're asking
What
"formally, in ZFC" and "if it's not a set then what is it" are incompatible requirements
okay yea that too
wait so like with the cat theory definition of a group
the morphisms are group elements right?
in NBG you can talk about classes I guess
Ok I’m dumb
I thought everything was a set in ZFC
which one?
you could be referring to at least 2 different things here
groupoid with one element
sure, you can define groups as one object categories where all morphisms are isomorphisms, and then the group elements correspond to the morphisms
sure
exactly
but cat theory goes beyond ZFC
Yes
ergo when you're asking for a ZFC formalization we're only exploring a part of it
hello people!
Ohhhh ok
oh right because every group is a subgroup of a symmetric group
So then how does the formalization work outisde ZFC?
magic
so there are a few ways to do this
NBG is a bad way to do it but it works for really crude purposes
vibes
since NBG gives you a way to talk about sets and proper classes
so you can talk about the proper class of all sets being the class of objects in the category of sets for instance
there are some issues with taking this approach in general though, since you can't talk about a "metaclass" of all classes and repeat constructions (e.g. for the Yoneda embedding)
so you need something more subtle
the two standard ways to do this are either through ZFC + TG (Tarski-Grothendieck axiom) or ZFC + exists a proper class of inaccessible cardinals
- ZFC and copium
- ZFC+large cardinals as universes
- NBG with class of all sets as your universe
- Tarski-Grothendieck with as many universes as you want
- A ramified type theory
these are equivalent statements, just depends on whether you like the setup of Grothendieck universes or the setup of inaccessible cardinals
- ZFC and copium
yea
yea exactly
either of these approaches is more common among category theorists/type theorists
though some people still like inaccessibles
there's also some reasons why the inaccessible approach is a little more expressive but either is fine
I still don't understand how hTop is not concrete
I've read the proof it checks out but like
how
oh yea it's a weird proof
I never understood it
like it's one of those proofs you can read each line and still not understand what just happened
ok so like reality check
if we have an ess. surjective functor between small categories, does it always have a section?
hmm
ess. surjective and full
I guess
sounds like this should be a form of choice
which means non-concreteness of hTop is a failure of "large" choice?
choomers btfo
Help, this chat is a fever dream.
Also, can someone enlighten me about the Axiom of Choice?
More specifically, what it is and why it amounts to the statement "The cartesian product of a non-empty set is non-empty."
The Axiom of Choice is obviously true, the well-ordering principle obviously false, and who can tell about Zorn's lemma?
Bruh, I'm a lvl 0 goon.
what does it mean for an axiom to be true?
Wtf is the axiom of choice, I need information.
wait is this a troll
the formal statement is:
$$\forall A, \varnothing \not\in A \implies \exists F : A \to \bigcup A, \forall X \in A, F(X) \in X$$
mniip
this is the "C" part of ZFC
Yeah, more like the Axiom of Incomprehension.
you can prefer to include or exclude this axiom from your assumptions
@compact tartan I'm baby, explain it to me like Im 5.
I don't think I can
but what if im 10 mniip
if you have a bag of bags, and you know none of the bags is empty, sounds like you should be able to pick an item from each bag
and there's no dispute about this if the number of bags you have is finite
but turns out it gets complicated in the infinite case
But what does this choice of ours have to do with cartesian products?
wait a minute, I think I just got it.
functions are related to cartesian products
the AoC is surprising because of the statements that are equivalent to it and statements that follow from it
existence of non-measurable sets or more famously the banach-tarski paradox is a consequence of AoC
TFW your prof gives a HW answer in class 
politics in a math server smh
partial fraction decomposition is beautiful and useful.
Until you have 5 terms in the denominator and have to solve a system of 5 equations.
Yikes.
this is just math history
Yeah, it's just the history of i.
good
And depressed cubes and the cubic formula.
there cant be any posssible way for cranks to misinterpret that right ?
surely
right? 
cranks?

amazing emote

😬
yeah, but what does crank refer to?
New veritasium just dropped 
crank is someone who is delusional in their claims about math
is this a video about cubics and complex numbers?
yes
(I haven't watched it)
yeh
math history of i
"led to quantum physics"
mostly talks about 16th century italians
bold claim
Wow... The cubic equation... Has square roots of negative numbers??? Wtf???
I'm sure physicists would have invented complex numbers if they needed to
not only is it bold, it is unsubstantiated
all it says is
"oh look multiplication by i is like rotation"
therefore physics
that's also the basis of conformal geometry
"it's like a number but if you square it you get -1" - shit physicists say all the time
I know you're being sarcastic but there's always that slight "what if" when it comes to you lol
I think this is build up to another video.
BRO LITERALLY
idk, just a feeling.
the same happened yesterday aha
prepare for "there is a hole at the base of physics"
Then why didn't they
Huh
mathematicians beat them to it
#excuses
mathematicians in shambles
complex geometry is the most based thing #Riemann #Poincare
Try again lol
Mathematicians make math, physicists find uses for it a hundred years later.
All is as it should be.
We need a Poincare fan club
Witten is better than most mathematicians

sometimes physicists shit something out and mathematicians are tasked with making sense of it
What if what?
sometimes it's as simple as "wait this is just group theory"
sometimes it's an open problem for 50 years
I know what if. You don't need to say it.

Poicare is really my hero
I have a suspicion that Green beat him to it
All math is but a prelude to p-adic hodge theory
and Jacobi
"it's like a smooth function but it's zero everywhere except origin"
It's integral is 1.
I think Green really beat him to it
- c (probably)
But I don't know enough about history and haven't read Green's original paper where he came up with his functions
ah yes, the green's function for the constant PDE 
Well
Hey, beating someone to it 100 years early
Is a big deal
I'd have to sit down and sort through it
I dunno if I have the patience for that though
how do you rationalize learning math history if there's so much interesting math to learn instead
couldn't care less who invented it and when
I like the development of ideas
Why do people write QED at the end of every proof? What does Quantum ElectroDynamics have to do with anything?
it motivates where the math your are using / learning came from
I enjoy history and I enjoy math
and I enjoy settling misconceptions about history of math
you see math is not just abstract ideas that exists with out human input. Every definition you use has a historical context
Some math stories are amazing.
I mean
that sounds like applications
yes you can apply math to other things
but why do I care who did it though?
Like when they gutted a ####ing guy because he drew the square root of 2 outside Pythagoras' house.
what do you mean applications
applicataions and or motivation
I find learning about the history of math and mathematical ideas very rewarding
I guess in the longer term I think I'm more interested in curriculum, education, and development of ideas
in my mind those things are not related to specific persons at all
Rather than doing pure math research for the rest of my life
but we'll see how gripping I find more research
It is interesting and I do like solving problems
its very interesting to see the historical development of ideas
it gives you a newfound respect from people like Riemann
I find history of math to be cool more from a history pov than a math pov
You find history of math to be cool from a math point of view
and you think the historians are full of shit
So the history point of view is bad
According to you, of course.
Lolol
Dami, you DO NOT THINK WHAT YOU THINK
math history from the history point of view 
math history in the 1940s 
Teichmuller reax only
Are there any new fields in math that have just emerged in the past decade or so?
homotopy type theory came about in 2013 ish
just the one?
What do you mean by "field"
probably plenty of others
But yeah I guess my thing with math history is, it's cool for general stories/it's cool to sometimes contrast how we think about things today vs how less enlightened people from 1700s/1800s thought about stuff
I guess, field to me means that it is, to a degree, separate from other math?
how old is condensed mathematics?
That's why I added "to a degree"
3 years?
what is condesned math
I have no idea
oh it's that shitsee guy
yet another "the most ambitious crossover in the history of math"
But I think it doesn't often inform how I look at current math, and generically I just prefer modern arts
Condensed mathematics is the (potential) unification of various mathematical subfields, including topology, geometry, and number theory. Ripped from Wiki.
Oh yeah condensed math is some new age stuff
But yeah I'll just say don't expect entirely new fields of math to pop up that frequently
shit like this is good leverage for constructivist propaganda
I should be all over this
but no time
still stuck on HoTT memes 
Since it turns out a lot of stuff is done by more incremental work or adapting existing math, which turns out to be still be very robust
idk this is some fields medalist guy saying this. Is this truly bs?
no one said it's bs
Condensed math?
Yeah nobody thinks it's Bs. I don't yet know what exactly it does but
lol Why do you call Scholze shitzee?
I'll be face to face with the enemy
It's how I pronounce scholze in my accent
'accent'
Scholze's passive observations probably destroy my entire math career lol
there was a recent talk about (also) condensed math that was quite accessible btw: https://www.youtube.com/watch?v=rec9uHzrDM8
Dustin Clausen, Copenhagen University
October 29th, 2021
2021 Fields Medal Symposium: Peter Scholze (http://www.fields.utoronto.ca/activities/21-22/fieldsmedalsym)
I watched one video by laurie or lurie
and they got the fourier transform definition wrong
and I stopped watching
What'd he say?
Also I'm p sure you mean the categorification one lol
Oh that's an alternative convention lol
I'm not sure why but I remember that conventions disagree
So he's not quite wrong here lol
It's non-canon
how many of 2pi do you write in your forward and backward fourier transform
It ain't a part of my gospel
Whatever makes the stuff unitary
I got a chuckle out of that
So iirc 1/sqrt(2π)
understandable
in CS it's common to use non-unitary fourier transforms
no factor on the forward
excuse me it's called Z_2
2-adics?
dyadic integers 
I can't believe I'm gonna have to learn all that shit
to be fair, a sequence of alternating -1s and 1s is and transforms into useful stuff
yuh, it's what my research advisor does
And what I will probably do
let me google hadamard matrix
yeah sure
they use that sort of stuff for coded excitation with large arrays
it's the shit that most spread spectrum transmission formats use
sounds about right
(pseudo) orthogonal sequences make nice coded signals
both from the spectrum/interference standpoint and from the SNR standpoint
"sIgNaL ComPrESsIoN"
I think his undergrad was in antennas or something
antenna engineering 
since i'm hired both at the uni and at a company that collabs with it
Oh nice
Signal processing is like my back up plan
I almost got a job as an RF engineer
but they found out I didn't wanna live in sacramento
So then I didn't get the offer
e.g. I would've worked for like 1.5 years
and then asked for a transfer
hadamard matrices
my algebra prof might give a talk on it next semestr
I feel like the part about shrodinger's equation was unnecessary in the veritasium video
He could've just left it at the history of the cubic equation
I don't think the discussion about the shrodinger equation actually added anything of substance
what does orientation look like on an 3-simplex
I only got to the cubic stuff
I liked his explanation of the cubic formula
Yeah
I've heard the story so many times, it's one of my favorites in math
It is good
Cardano, Tartaglia
And deserved to be on YouTube
I think it's way better than "Galois in a duel" meme
They're both memes
What really needs to be showcased
To a wide audience
Is Poincare and Klein's race to prove the Uniformization theorem in complex geometry
Now thats an exciting story
And I don't know the full story
But I wish I did
Oh hey fourier was the first to speculate that the Earth's atmosphere traps heat coming from solar radiation
That's pretty neat
Well at least first to speculate it in a real, academic sense with mathematicalisms at the foundation
It's fun to read old books on science
"Scientists speculate there could be other galaxies"
Am I the only one who thinks that Nasa does fake shit?
Look at how these nuts are fliying, it looks so fake.
2013-01-25 - Another Fun Friday video! Everyday life in weightlessness holds many surprises. CSA Astronaut Chris Hadfield pulls the lid back on the secret world of mixed nuts in space.
Credits: Canadian Space Agency and NASA
Expedition 34-35 Web page: http://www.asc-csa.gc.ca/eng/missions/expedition34-35/
Find out more about this video: http:...
The lighting of them looks like the CGI of a highschool project.
nasa
canadian space agency
It's made on the ISS.
anyway, looks fine to me
im sure the video is touched up (obviously, the label is blurred)
but that would be very impressive cgi considering the reflections on the aluminium foil
The way it is fliying looks so fake, as if they were putting a 2d clip on a 3d.
...i dont see it
thats... a different video
are you just trying to spread conspiratorial bs in a random big server
screw off
Nah, bro I am actually triying to discuss it with people.
Cause if it is really all fake I would be sad.
What else is there to discuss other than that it looks fake to you?
not sure that bringing up a comment from a totally unrelated video is a good faith discussion
you havent tried to explain why it seems fake other than "it looks 2d", but it doesnt look 2d to me
and the reflections on the foil and the can make the depth fairly clear
at least the people who find reptilians in video compression artifacts have an image they can point to
nah space is real, NASA is fake
Lol
NASA is a big money laundering scheme
they say every space shuttle launch costed billions
where did that billions come from, huh?
clearly illegal black market activity
pablo escobar didn't die and is just head of money laundering space agency
faked his death
actually space stuff would probably be a surprisingly effective way to launder money rn lmao
eh i guess its too public facing/sensationalized
but like
no one knows how much shit should cost
I would support a nasa money laundring scheme if it somehow managed to further space travel and junk.
if spacex says a rocket costs $800 million
who are we to argue
maybe its only $400 million
meanwhile, if you claim that car wash costed $60, im gonna get suspicious
Markup for government purchases is pretty crazy in general.
Seems plausible for space stuff too
yeah but it did bro, trust me
reporting income tax on your car wash
sales: 7
total earnings: $522 000
who's saying I'm reporting income tax?
I actually really hope that stuff is real.
Cause espacilly stuff like LISA is big shit (Even though that's from ESA)
why focus on such out there conspiracy theories instead of ones that actually make sense for the government to pursue
like mass selling stocks in early march 2020

what shape is what
the object itself is an abacus
I get that but the shape it is used, I know there is a name just cant remember?
dicones?
yes but inverted
I see
but tbh id call those closer to "saucer shape"
Anyone actually able to quote stuff like like EGA or Harthshorne. Looked up books saying intro to AG and a lot of people mentioned it, reddit called finishing them a rite of passage. Im doubtful becsuse both look long and tedious to go through in full.
i read hartshorne in undergrad
i would not recommend it
ega is pedagogically terrible and only really valuable as a reference
hartshorne is fine but not great
oof
based yamin
yeah like, i read ch1 so far, and all of it feels like a continuition of complex geo
I should get back to hartshorne soon 
Stack of frusta
Ch1 of Hartshorne kekw
Do you also enjoy dragging ur balls through broken glass?
huh
Are there professors in this discord?
every professor is busy, every professor is in every uni
I'm wondering who all the smart yellow namers are
are you guys grad students? advanced undergrads?
We are legion
ReLisrixallt we are all different ages lol
There’s hsers, undergrads, grad students. There is one professor
He’s also a cat
Actually maybe two now that buncho graduated
And there’s zeta
Lol

i am a second year undergraduate
So how does one achieve the coveted yellow name?
unknown
you must be a good role model and accepted in the community or something
idk

i should know
No
why 
happy belated birthday

tomorrow's my birthday
its your birthday!?
Oh yes I remember
Happy birthday!
I’m 2 days older than you
😊
happy bday in advance 
Also I forget did u used to have like
happy birthday
janman
I think I remember that the bios were the same or something
But I guess ppl didn’t read ur bio
Hence the new name
Actually
👑

Me in a nutshell
Chmonkey
Lmaooooooo
Follow up btw
oof
wait, read my about me is janman?
wtf
i see a random person with generic roles and a generic nickname lol
or either nJanmoid
i thought it was someone new
Fuks
Maybe this is a dumb question but can you have a sequence of functions (f, f’, f’’, …), where f’ means derivative? Can such a sequence “converge”?
I’m thinking about how polynomials “converge” to zero, some functions “converge” to e^x, and some functions diverge
Polynomials converging to 0 
But I think you can certainly have the sequence of derivatives
Provided f is infinitely differentiable of course
Yeah
And it's meaningful to interpret its convergence as any other sequence of functions
Any other sequence of functions? How do those work?
The one I'm familiar with is pointwise convergence
F_n converges to f if for any x in the domain of f and any e>0, there exists some n such that |F_m(x)-f(x)|<e for all m>n
Basically just the usual convergence but for images of your functions
it depends on the norm you choose
Ah okay
for some suitable sense of usual 
sup|F_m(x)-f(x)|->0 as m->\infty?
This sounds like normal convergence just saying fn converges to f if the sequence (f1(x), f2(x), …) converges to f(x) for all x in the domain
x ranging over the domain
Yep!
the for any x quantifier goes after the property
Lit lit lit
hey guys, i'm currently in grade 12 and working on a math investigation (for those of you who know what the IB is, i'm working on my math IA) and was planning to do an engineering optimization problem, do you think it's a good idea to do something simple like the most efficient rocket launch trajectory, my requisites are it can't have complicated physics but the mathematics have to be like simple calculus(as a reference it's my first time studying calc but i could learn a bit of more sophisticated calc if neccesary)
most efficient rocket launch trajectory
Requisits can't have complicated physics
I'm guessing air resistance is negligible
you can do a much more simplified version of that problem
if you throw an object with, say, a catapult, at which angle should it leave the ground so that it reaches the largest horizontal distance possible?
Oh you mean that?
That's rather easy
If there are no walls and air resistance is negligible, just calculate de derivative
I made an animation of that for physics in my senior year
(that's just my suggestion, cuz the other problem they gave is out of their reach)
but yeah, it's like beginner level physics and you can use calc to optimize it, so
@pale orchid I think you learn about Kepler's laws in 12th grade, so it might be possible to solve using elementary physics and some calculus, the best trajectory for a rocket. Assuming boundary restrictions on the gravitational pull of a planet
knock yourself out then
I mean they said it was an investigation thing
the most efficient rocket launch trajetory is also a weird question, what type of optimizations are you looking for
least fuel consumption is probably like close to enough for escape velocity, and just use planets as catapults
solve triple body problem
@gloomy marten @pale orchid I've just read your discussion and i think I'm gonna use the catapult idea considering air resistance and that i think I should get the difficulty required, thanks for your help :D
but 2^(1/2) is also irrational,
is the theorem trying to say otherwise 
it's not though
the proof by fermat's last theorem is simply not valid for n = 2
but is this proof actually valid tho?
aahh
ig maybe? i mean its a theorem proven to be true, so i dont see a problem
the normal proof is really simple though
Some people were saying "circularity" something something but I see no way the usage of this is circular.

it might be, I don't know the proof for fermat's last theorem
how is this circular?
anyway
if 2^(1/n) is rational, exists p,q coprime such that it is equal to p/q.
2q^n = p^n => 2|p => (by sub) 2|q. contradiction (for n > 1) qed
fun
fermat's last theorem might use this fact within the known proof
Proof is valid, doesnt look like Fermat’s last theorem uses this fact
Or you can just stop before last line and say a^n is even and b^n even which is contradiction
a^n even because divisible by 2, b^n even because n>=2 on both sides implies such.
andrew wiles is most famous for his proof of the modularity conjecture, which finally resolved the famous, long-standing problem of whether the cube root of 2 is rational
lmao
too bad it cant prove square root of 2 is irrational
We need a stronger version of Fermat's Last Theorem for such sorcery.
Is it possible to write like this? r ∧ n ∈ ℕ, x ∈ R?
That r and n are natural and x is a positive real number
you can just use a comma
Where?
$r,n \in \mathbb{N}, ,, x \in \mathbb{R}$
Edd
Ohh thanks!
Just another quick question
If I have a three statements equation
Where do I say this about r,n and x?
So I have an equation with three statements. I want to say that r,n is natural and x is a positive real for every three statements
I've never done this before
Right now it looks like this
And I don't know if it's right
idk why there are ifs
but you can just separate the stuff with commas as you did
There are three different equations
for example
and you can separate the conditions with commas
but honestly you should just describe r,n, and x BEFORE you define P
cuz you're writing the same thing over and over
yeah I was wondering that. How do I do that? just put it infront of P in brackets?
like this
you can write it above and use words
nothing wrong with words
given r,n \in \mathbb{R}, etc,. the function P is defined as
Thank you so much!!!
I'm in my second year in highschool so you can image that this is WAY a head of my knowledge
Or thrid maybe if you translate it from I live.
This all started with 3b1b video, and then I got obsessed
that's aight
there's no need to use symbols for everything, especially if it makes things more difficult
Yeah but if I don't state that I will get like 100 solutions.
what i mean is you can use words and that doesn't make it any less correct
Riight
But this kind of looks cooler. Like if I show it to my teacher
But she won't really care
e.g. "consider the numbers $n,r \in \mathbb{N}$, $x \in \mathbb{R}$. We define the function $P: \mathbb{N} \times \mathbb{N} \times \mathbb{R} \to \text{(idk what your codomain is)}$ as:
$$P = 0$$
Edd
just as an example lol
Riiight
It's kind of hard to understant the P: N x N x R ->, part
never done that lol
It's just a function that takes ordered pairs of natural numbers as input
what did you use for the spacing?
Wait NxNxR so I guess ordered pairs of natural numbers and one real number as input
\,,?
\,\,
So ordered triples where the first two entries are natural numbers and the last is any real number
@pale orchid sorry if this is bothering lol. Did I do it right now?
n and r are both known values
we want to solve for x
I should write that P is also known
sure i guess
So maybe it's less than a function and more than an equation???
i mean, you have a binary relation that gives one output in R+ to any input in N x N x R+, so
i guess what i would change is that i'd write P(n, r, x) instead of P
yeah I didn't really know what that part meant. P could be anything but I always say that P is equal to erf/sqrt(2)
Or P could be anything between 0 and 1
i dont understand what you mean
P is what the range of the probability density should be.
so (r+1)/(n+2) -+ x give the range. And the area under that range times (n+3) should equal P
idk what you mean by range here
So I am calculating probabilities of probabilities
the range is a set
Oh
i assume you mean to fix a value of n and r, and then vary x
to yield a curve P(x) for a fixed n and r
and then varying n and r yields a family of functions
and the definite (probably improper) integral of P(x) yields the probability of x being within some range of values
Yes. I believe so(?)
Like lets say for instance a factory produces 100 cars where 2 cars have defects. What is their true success?
In %
sounds like a probability distribution that already exists and you should google how to write properly 😛
Have not found anything.
I used laplace rule of succession
Because I want to find the two values that are most likely is the car producers succession
I would love to find a formula for it, that isn't this complicated and hard to calculate as mine is.
i would really suggest asking in one of the questions channels tbh
and regarding notation, a quick read on what functions are and their notation on wikipedia should kickstart you
for specifics on latex, the latex help channel
Thanks!
yooooooooooooooooo
im actually enjoying doing engineering for once
analyzing trusses is so fun
it's like solving a puzzle
truss more like sus
trussy baka
kinda truss
truss 🥴
stun seed analysis
edd don't you want to know what dnusses are : (
dnusses deez nutz idk
that i answered you with stun seed analysis should've been clear enough
I don't get it
the fundamental theorem of stun seed analysis goes as follows: "read it backwards"
i will crucify you

you are an animal
I've lost all respect for you Edd
anyone know anything about the Churchill scholarship?
yes
what do you know nYaminoid
i want to know too & its just funny
@bronze pelican
I applied to it
i didnt get it tho
this webpage has info about applying https://www.churchillscholarship.org/apply.html
Churchill Scholarship
o fuq the deadline was yesterday
I was just curious because a research program in math straight out of undergrad seems strange
its sort of like a masters actually
is it not a research thing?
yeah I read through that
sounds like you get material vomited at you and then kinda die
but then if you survive you might actually learn some math
too many
I wish i had that at my school 😔



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