#serious-discussion
1 messages · Page 79 of 1
once its published, come back
good for u
Only over function fields though
<@&268886789983436800>
wtf fuck off
@cold needle
I wrote what I interpreted
then got told it was kinda wrong immediately after
let us game son I’m ready to learn
the inverse function theorem is basically: if the best linear approximation at a point to a function is invertible, then the function is locally invertible around the point
why is this plausible
I can give you an intuitive answer but not a formal one lol
well the best linear approximation at p is the linear map Df(p)
and what that means is f(x) = f(p) + DF(p)(x - p) + o(x - p)
o(x - p) meaning terms going to zero faster than x - p does
Mhm
these are negligible if you get reeeealll close to p
Yep
so rrrreeeeeeallll close to p you have f(x) = f(p) + DF(p)(x - p)
not = but you know
squiggly equals
Yes
ayaya
so if f(x) ≈ f(p) + Df(p)(x - p) then you would expect to have something like f^{-1}(y) ≈ p + DF(p)^{-1}(y - f(p))
did i get that one right lemme look
yeah
please forgive me using f and F interchangeably
mfw I didn’t even notice (I am converting mentally 🤓)
some harder thinking and you might even say f^{-1}(y) = p + Df(p)^{-1}(y - f(p)) + o(y - f(p))
the actual proof of the inverse function theorem, at least the one in spivak, is just making sure you can actually go from "really close to invertible map" to "invertible map"
implicit function theorem
the corresponding linear algebra thing is solving systems like Ax + By = 0 for y in terms of x
why
well say you have a nonlinear system of equations f(x, y) = 0 and you want y in terms of x near a point (a, b)
when you take the linear approximation at (a, b) you'll get a linear system of equations (a breeze to solve. so easy)
f_x(a, b)(x - a) + f_y(a, b)(y - b) = 0
i probably should have mentioned i wanted B to be square
any determinant needers in the chat

so this is the best linear approximation to the nonlinear system of equations f(x, y) = 0 near (a, b)
solve.
to get y in terms of x you need f_y(a, b) to be invertible
the implicit function theorem says that, if you can solve this approximating linear system, then you can solve the non-linear system locally
I sort of see why they’re the same
in linear algebra, invertibility of a matrix and the condition of whether you can solve a system of equations involving the matrix are the same
so of course the theorems in calculus should be the same!
proof: just try to adapt the linear algebra proof to calculus
I never really learned rank stuff properly so that’s the one I don’t know or understand
if the rank of a matrix is r then it can be put into the form
I_r O
O O
I_r the r by r identity matrix
this is the only fact you need to know for the constant rank theorem
(the Os may be of different sizes but they're all just matrices with only zeros)
Yes
so well
you can probably guess how it's going to go
if a mapping's best linear approximation looks like this I_r OOO thing then the function ought to look like it locally
there is one small issue
I’m guessing it’s just if constant rank within nbhd then you guarantee invertibility within nbhd
not invertibility
constant rank applies to maps from any R^m to any R^n
but yes constant rank is the condition
only square ones can be invertible, and, in that case, invertibility is the same thing as maximal rank
anyways
if the mapping looks like this, i.e. looks like (x_1, ..., x_m) -> (x_1, ..., x_r, 0, ..., 0), then that forces its derivative to have rank r not just at one point, but near the point you were considering
so constant rank is a necessary condition for the result to hold
it is also sufficient. cool
because a matrix has rank at least r if it has a non-vanishing r by r minor, the rank of a matrix cannot drop suddenly
so you just have to make sure that the rank isn't jumping near your point
in particular if you have maximal rank at the point you have maximal rank near the point
this is how you get the inverse function theorem out of this
when square maximal rank is equivalent to invertibility
ahh ic
that one’s cooler than the other two
maybe that’s bc I’m less familiar with it though 😛
so true
Thank you for explaining
tu's manifolds book has an appendix going over all of this
I don’t think I’m ready for this subject
I mean I understand the concepts, I’m just an absolute Cox-Zucker when it comes to proofs and manipulating objects lol
but ig that means I don’t understand very well huh? 
why chatgpt chan nit solve elementary algebra problems?
cas is artificial inteligence?
ChatGPT is good with providing correct definitions but can't do even simple arithmetic correctly
Funny enough
it helped me a lot with my fluids hw
LOL
I had it solve some NS for me 
nah, it's not even good for this as well
i saw someone try to ask it what the third isomorphism theorem was and it produced a blatantly wrong statement
literal nonsense
yeah it does some errors in defn as well but not as much as in computations
isn't stokes thorem or generalized stokes thm
yeah
That’s Stoke’s Theorem yeah
Man I remember
When I learned it the first time (or Kelvin-Stokes, rather)
And Moth was explaining the intuition to me here
That feels so long ago but also just like yesterday
Lmfao, Stokes at its finest
you can convince chatgpt into believing anything
Even if ChatGPT gets better at math, I will still study math tbh
There's no good if I can't verify if a proof is correct
So true
Do you think it will get better at math?
It doesn't have any intuition
It doesn't need intuition
Math a lot of times boils down to knowing and applying tricks
And AIs are way better than us when it comes to that. Just look at AlphaZero

does it mean it will not be able to come up with "new" proofs ever ?
These mfs discover new tricks in chess. I don't see why it's not possible for math
Oh, i'm sure it will
that'll be cool specially the algorithms which will make it possible
There will be no algorithms for it tho 
At the very end of the day, it's a hell lot of knobs being tuned just right so that it stumbles upon something
I think there's technically an algorithm to generate proofs: just enumerate all possible combinations of logic symbols. But it's so useless that you better just study math and do the proofs yourself
hmm Can we solve open problems with AI somehow ?
like using that algirothm of enumerating all possible combinations of logical symbols
We did solve open problems with computers before
hmm but mostly using it's computational powers ?
It's like enumerating all possible games of chess to find the winning moves 
how does this algortithm halt tho ?
like how does it get to the "correct" proof
You don't

that's the point of halting problem: you can't decide if a given program halts
this one halts because we know all chess games must terminate
but there are statements that are correct but not provable
ig some of the open problems fall into this category ? like we don't know if it's provable withinn the given axiomatic system
So the task is to prove that it's unprovable within the given axiomatic system
CH ?
Nah, We proved that one is independent
Godel's first incompleteness theorem implies that for any such consistent formal system, there will always be statements about natural numbers that are true, but that are unprovable within the system.
I think the second theorem shows that the consistency of the system is such a statement
either a system is inconsistent, then it's demonstrable, or it's consistent, but it cannot proves the consistency of itself
Idk, I don't study logic. And for good reasons
idk if it's silly que but how do we extend that to talk about other domains in maths , like statements about abc... that are true but that are unprovable withinn the formal axiomatic system or we don't ?
hmm then why godel's 1st incompleteness thm talks about natural numbers specifically
It's the weakest system you can possibly hope for
Anything below that is too weak to be interesting
ohh yes So it's godel's weak thm 
isn't this the theory of singularity
Can anybody help me take this godforsaken calculator off test mode i'm about to claw my eyes out
what calculator is it
ti nspire?
yes cs ii t
i have the application
windows is recognising the calculator
but the application isn't
I usually just use another calculator of the same model
do you work for texas instruments and want me to purchase another calculator?
i graduated
skill issue



thank you both this has been enlightening
if your only problem is getting it out of test mode there should be plenty of help online
could you not find anything?
well my problem is that this is happening
getting it out of test mode should be fine assuming the app they made for it works
oh
the only way to do it through a computer involves TI Inspire Computer Link
i have my calculator plugged into the computer
the computer is turned on since i'm using it to send these messages
and windows recognises it as a TI Inspire CX II-T
but somehow the app can't see it
oh god. i just realised that the free app doesn't work with my calculator and that I have to buy the student software
Texas instruments my beloathed
damn right
Be nice
Be nice
english totally robbed latin for like half of its (english's) words
@solar hawk what does your name mean
It doesn’t really have a meaning
Is it partially made of my initials though
Amukh
I would explain but I don’t wanna dox myself 😭
Don't
In hindi mukh means mouth so a mukh means mouthless 
wait, I didn't dox you right? Should I delete my comment?
thanks xD
mukh means mouth/face in bengali too, what a coincidence
I mean north languages are pretty similar so not a big coincidence
ig
Chmonkey
im back
why did you name your account chmonkey
Lol “bohneur”
No it’s in the name of the gif they sent
hi dqstupid
hey darq can I talk to you for a bit
yes, but you recognized it
sup dummy cat

hssssssssssssssssss
yo guys i really need hhelp
i have a finaly exam after tmrw
and i cant find my geomerty book
its called "geometry 2018 student edition"
if anyone has it please dm me
search up Pontryagin
the dude was blind from like the age of 14 and has quite a bit of theorems named after him
mathematics is, with one viewpoint, entirely abstract so yes probably
That's how computers do it
Is Euclid the best Geometry book? Not for someone in junior high but for an older student/mathematician who'd care to learn it for some unknown reason
Any recommendation which book I should get, after the "Book of Proof" in terms of preparation for university?
terence tao's analysis
I read the discription. Sounds quite interesting.
and gallian for aa
What is aa?
abstract algebra
axler for linear algebra is good too
these three are like classic recs for anyone begin the next step
So for abstract algebra gallian, analysis terence tao and linear algebra axler?
I'd say pinter for abstract and ladw for linear.
I am not so sure if I get them through till uni starts 😦
Axler is not a good book. Determinants are an important part of LA, and his "determinant-free" approach is mind-boggling.
So I should swap axler with pinter?
Swap axler for ladw
Ladw?
I like Pinter better than Gallian for the exercises, but I think Gallian is fine
Linear Algebra Done Wrong
Axler is good
"determinants are an important part of LA" 
They are!
Ok quick question. What do you think about the "Book of Proof"? For introduction purposes.
Bc I am currently reading it.
It helps you learn to write proofs
It's useful
Axler does eigenvalues and eigenvectors before he does determinants though
now that's sus
Yeah
The questions is, am I able to work through those books till uni or even do I have to?
kind of worried
a bit
Those are all textbooks for courses you're expected to take in your first year or so
If you're American you might take 3 years going through them. If you're a Brit it might just be your first year.
So it's supporting material after the courses?
German.
No, it's the textbook for the course.
Ah. I'm not as familiar with the german system.
You get textbooks for the courses?
Thats new
Yes.
Interesting.
You need to read the textbook as well as attend lectures
Generally there are not solutions to exercises in textbooks at this level
I think Pinter includes some hints
And solutions to very simple computational problems
You generally know.
ok
Man I wish I could do more advanced math... I find those topics I see around so interesting. And then I realize that I am not even at the beginning.
Just start studying and keep studying and you'll get there
I'm starting my PhD in a couple months and I'm still just starting off in math
What topic?
Math
I'm going to be grading probably calculus
And taking advanced courses
Then in a couple years doing research
What do you do in calculus?
Sounds interesting.
I will probably have a discussion section, and then I will grade homework.
That is my guess.
Hm.
Unless you mean, like, what is calculus
In which case it's calculating derivatives and integrals
That would have been my guess.
So in calculus you learn to compute things like this integral: $\int_{0}^{1}x,dx=\frac{1}{2}$
Zorn's Lemming
With compute, you mean what exactly? Typing it in a program?
Calculate
Yes, the American curriculum is a bit slower.
Lots of people don't see calculus until they start college
Ok. In Germany we see integrals in "Gymnasium". I don't know the correct school system, so...
But it is the "highest" school, but still under university.
Thats a good integral
In America a gymnasium is where you go to do exercises, run on treadmills, use those bike things, lift weights, etc.
xD
It's the best one that I know.
I am still wondering which books I will have to buy when i enroll uni.
It depends a lot on the professor teaching the course
Because it could become a problem, if i buy a book which i then won't use.
At my UG some professors used Pinter, some used Gallian when teaching algebra
It depends on who's teaching it when
so i should wait with buying?
Buy if you want to self-study before you start
If you only want the books you'll use in your courses, then wait
i mean i want to study math, but i am worried that i might buy books that i will later on not use. i mean i only have a few months till uni, so...
I am at the last big chapter.
I am starting uni. So I am not sure.
Propably linear algebra, i guess.
linear algebra 1 and analysis 1 is the standard for first sem in germany
maybe also an intro to programming
Are German undergrad programs more analysis-oriented than algebra-oriented?
Yes
at least at my uni you are required to take analysis 1, 2, 3 which includes measure theory and analysis on manifolds
and algebra 1 is optional
Oh, wow.
?
That is a very strong analysis bias
What do the germans who want to do algebra do?
Suffer?
you can take like numerical analysis instead of algebra 1 lol
maybe other unis are more algebra pilled
Maybe
my uni has a big numerical department
Ah that makes sense then
Where do you study?
Do you get books recommended by your prof? Like at the beginning of your courses?
yeah profs usually give literature recommendations
or say what book they are basing their course off
i like the approach, idk why though
Do you have any German textbooks or do you just use the popular ones in English?
I have this one german category theoretical algebraic geometry textbook
and one on numerical analysis
but nowadays I just use online pdfs
Wait... are most math books free online pdfs?
?
But you need to sign up.
usually I just search for "<book title> pdf" though lol
fwiw you can log in with your uni account on springer and get books that your uni purchased
So in general just the problems.
but if the pdf is longer than 100 pages, how do you keep track where you left off?
I use obsidian to read pdfs
if you close the app on page 69420 then next time you open it again it will resume on page 69420
is it free?
yes
git gud
I was looking up this book. Do you mean "Contemporary Abstract Algebra" by Gallian?
yep
k thanks
Heard good things about it
yeah dude
i feel like uni is needlessly hard in germany
How have your opinions gotten that bad
use LaTeX dummy
it's mathjax + markdown
@storm sage what’s your youtube channel
also I’m going to get you to help me learn algebra
also also I think I’m going to become algebra pilled just so I can get away from point set topology

@woven whale I like projective :3
I am planning on changing my minecraft name to that too
about me
I forgor my MineCraft account :sadge:
Maybe once I’m a big boye and can play games as much as I want

🫂
They always were
I wanna learn numerical analysis 🥺
Hello! This is just a YouTube channel where I upload random personal projects. My friend made a Discord server for it, if that's your thing: https://discord.gg/FVeSn5XFRy If you'd like to suggest a Desmos graph for me to play, you can either email me or put it in the Discord server. Hope you enjoy your stay on my channel!
Sure thing fren
what is wrong with point-set topology?
open and closed sets
why’s there gotta be two :sadge:
and then there’s CLOPEN too like wat the fuck
it’s that hitler video all over again
this really isn't that confusing
no idk what I’m complaining about LOL it’s just hard writing proofs :sadge:
most of basic point-set topology is supposed to be incredibly straightforward
it's good proof writing practice
shh let me whine in peace I’ll come back to it one day :3
I do the algebraic analysis 👍
become new eric tao
if you do commutative algebra you are going to have to grapple with open and closed sets
if you do analysis you are going to have to
like
this isn't really something you can reasonably avoid
yes I know :hehe: but it’s so much easier than the spaghetti that goes on in m*nifolds
im aware what it is
Doesnt change my opinion
use LaTeX dummy
What is LaTeX? Have only heard of it.
It's a language for typesetting documents
It has very tools for typesetting math and so is very popular in academia
no, its a language
so you need a program or software to compile it
but you can write it with any text editor
hm, interesting
like how you can write C++ in any IDE, but you need gcc or something to compile it
sure
there are dedicated latex editors though
but again those dont usually come with a compiler
the standard latex distros on windows are miktex and texlive
idk about other platforms
and then you can write it in whatever text editor you prefer, though there are dedicated latex editors (e.g. texstudio)
there's also overleaf, an online latex editor
good for collaboration on the same document
vim+TeXlive is the way to go
personally i use miktex + texstudio
overleaf
but overleaf is the most beginner friendly
no need to install anything
it holds your hand a lot
might give it a try in the future.
by the way... i was wondering about implications. Why does math have two symbols for that? Like an single arrow and a double arrow?
Are they used in different ways?
like $\rightarrow$ vs $\Rightarrow$?
just down to the preference of the author
no real difference
anecdotally $\rightarrow$ feels more common among philosophers and logicians, and $\implies$ feels more common in most other settings
namington
Though single-stroke arrows are used for many other things in math as well, so double-stroked arrows stand out more
yeah i personally prefer \implies since its less likely to get confused
my uni has a semesterly latex course organized by the faculty
obligatory?
$\exists f^{-1}\colon ℝ \to ℝ \implies f$ is bijective
no
namington
wait people use rightarrow for implies Lmao
yeah, ive only really seen the single arrow used in the context of formal logic or philosophy
(and in formal logic its because theres often a distinction between syntactic and semantic implication)
what uni will you be going to?
Still not so sure.
I think LaTeX is not too hard to self-learn
You think? I looked up some and it seems like HTML code to me.
Or in other words, complex.
it is very different from html
for one it is not stupid
and its meant for typesetting documents, not webpages
pikachupikachu
I know. But it still seems so new to me.
But I guess that comes with practice and stuff.
everyones new before they learn something
true
read a few tutorials and whatnot
any recommendation?
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Overleaf saves the day again.
For some reason I forgot to respond to this all day but I opened my computer and this was one of the first messages shown since it takes a sec to load
So I remembered it
Honestly? Numerical analysis I could see being interesting
Like idk much about it but
I'm guessing the idea is like, hey here's some shit you may wanna do
Solve some matrix equation or differential equation or whatever it may be
What are some methods to estimate shit? How quickly do they converge? etc
Probably not my cup of tea but I could appreciate it
I have analysis psets from a couple years before I took it and one problem they had is what I imagine numerical analysis to be on some level
Like that's kinda nifty. The coding part would probably make me wanna commit sudoku, healthy as it is
@sharp mulch maybe confirm I'm not talking too much shit?
Anyway my thing earlier was more just the fact that you didn't have to do algebra lol
Huh what
Just like, was that a total mischaracterization of numerical analysis lol
A big part of numerical analysis is numerical linear algebra so solving Ax=b, factoring A=PLU/LL^T/QR/USV^T, multiplying C=AB effectively
Another big part is solving ODEs/PDEs
And you do want to have error bounds and convergence rates
Gotcha
have you heard of LU decomposition
The classic
PLU or LUP is just LU with some Permutations
optimization and machine learning 
cool stuff id say
i took a computational stats class
all my exposure to numerical linear algebra was in one class
i enjoy the topics
im assuming ur in academia
so what specifically do you study
no
brotherImusttalk1234
brotherImusttalk1234
Huh
L moment
use \mathfrak if you want to have a book that feels like it has been written in 1950s
$\mathcal L$
ally ❤ (semaluhtounuyulohowwah)
$\mathfrak L$
numbpy (anti-glomed)
$L$
MochaOhwelp
I once attended a talk on Lie algebras where they referred to mathfrak as the "spooky vampire font" and honestly valid
$\mathfrak{I've come to suck your blood}$
cali5nia
Checks out
weird flex?
is that seriously what $\mathfrak{y}$ looks like ew
dirichlettt
I was wondering why there was a random eta in there xddd
wtf
eta on
drugs?
$\mathfrak{S}, \mathfrak{G}$
anamono for anamono 🍓
Why are you mad at y? Look at k!! 😱
,, \mathfrak{Transylvania} \subset \mathfrak{Romania}
wraithlord_kobordism
$\mathfrak{J} \mathfrak{I}$
anamono for anamono 🍓
Professors using p and rho as variables except so much worse
yo dm me if you can help me with something that involves joining a server a using the search bar to find something
Chmonkey
Yo is Khan Academy and a few past papers enough for an AP Exam
Most likely not
1-905-442-4151
The hell
what else would you recommend
do they cover all of single var
yes
Okay , So Linear transformations are a type of vector valued functions that maps V to U such that L(x+y) = L(x) + L(y) and L(ax) = aL(x) where x , y ∈ V and U respectively and a ∈ F(X,+,×) have I understood this correctly or Am I missing something ?
what are F and X
They mightve been hacked
Same message in 3 different channels on the same minite
any field over a set X
and X?
a set
so what is the relation between X, and U,V
Because you can't leave that unspecified
hmm U and V are any vector spaces and F is a field over a set X , wdym by relation between X and U,V ?
That makes no sense, a linear mapping is only defined between vector spaces that are over the same field
ohh yes right So vector spaces U and V are defined for scalars belonging to X (i.e over the field F)
So if F is your field then your v.s. U and V have to be over the field F and a linear mapping from U to V is any mapping that preserves the alg str.
If your field is X then yes
yeah sorry I forgot to mention that
looks like some weird character from gumball
Does it hold for finite elements fields as well ? (Sorry for the ping)
what does over mean
like a vector space is over a field means it gets it scalars from that field
what does a field over a set mean
It means the elements of the field belong to that set
so X is F?
F is a algebraic structure equipped with two binary operations and it's elements belong to the set X
the definition doesn't care about that but a lot of the theory developed in linear algebra is over fields with characteristic zero, and these are infinite. the mapping N^{X} to the field F defined k |--> k.1 is injective, indeed if for m, n in N^{X} if m.1 = n.1 then (m-n).1 = 0 and by the fact that a field does not have divisors of 0, m-n=0 which means m and n are the same therefore proving the injectivity of the said mapping
N^{X} is just naturals without 0
Haven't finished learning it entirely lol, mostly axler, and morton curtis and a bit of this bit of that, did some abstract algebra from hungerford to make myself with some of that terminology, helps out a lot when you get to linalg knowing some group thelry and basic facts about fields like the fields of characteristic zero being infinite
Also cosets
so you need abs alg for linear?
Nope.
ik what groups,rings, and fields are but idk anything further
trying to understand the mathematics behind general relativity a bit better. I know it's a long shot, but does anyone have any useful recommendations on books about Rieminnian geometry/differential geometry?
I think people like Wald? It seems like it discusses a good bit of math
But yeah your background is pretty relevant
bye they didnt even help me i literally cheated my way to finish
is there a general number of classes a math major should take per semester in uni?
i remember i took 6 classes per sem?
but it differs from each uni
thats fair
i can send the list of what i have to take if that helps
im ofc talking with an advisor but rn its by mails so its rly slow
i think your advisor would give better opinion than me lol
thats fair
so, even if it's slow, it worth asking
basically im gonna be taking at least algebra 1 and analysis 1
sounds good
because the stuff in year 1 is generally easier, i took around 4 classes only in my last year
but yeah im in quebec so its different, i basically start as a U1 student
each sem
i see
did you go through the syllabus or have you bought the books?
For the classes I’m taking next semester you mean?
yep, i will usually skim through the websites of the class in the previous years and take a look at the table of contents
Thats a good plan yeah
I haven’t chosen everything yet cause I’m waiting on something but I can do that for the 2 I’ll be taking at least
then you can try reading those stuff online and see if you can get used to them
Yeah I’ll try that
i didnt prepare well enough for my analysis class in my first year, i failed it...
Is it because of difficulty or the different approach to math
latter
That it’s like challenging
Yeah I heard everything is proof based
Well, a lot at lest
I was so not used to the thinking process of it back then
Is it the same for algebra 1
I mean it does say methods of proof so I imagine so
Im just not sure the pace that’s expected to do everything
Anyway I’ll think it over and just wait for more answers from advisor thx
I'm not sure if it is abstract algebra
you'll have to get use to stuff real quick in year 1, then you'll be more comfy in later years
Mathematics & Statistics (Sci): Sets, functions and relations. Methods of proof. Complex numbers. Divisibility theory for integers and modular arithmetic. Divisibility theory for polynomials. Rings, ideals and quotient rings. Fields and construction of fields from polynomial rings. Groups, subgroups and cosets; group actions on sets.
That’s the info given on the class
So yes I think
ah
I should probably take a good look at my linear algebra notes from half a year ago before I start this
the divisibility and on stuff is kinda hard to understand at first
tbh it really depends on the lecturer/prof
but it's fun if you understand those!
Not sure what’s meant by divisibility theory
I already had a class that went into methods of proofs and complex numbers tho
for that, you don't really have to learn in advance
I'd trust lecturer/prof's design of studying pace
(although some don't really care XD)
I just hope I get lucky
It’s for an honours class so it should be fine
Oh also last thing before I go
yea?
I have 4 classes of algebra and analysis in total required
Is it better to do them like in a row
hmmm
Aka not skipping a semester of one of those
yea
i bet you'll have some guidance when your in the welcoming week of the department
senior students might help planning
(that's what i get, I'm not sure if you have the welcoming week though)
Pretty sure I do
that's great then!
But yeah ill ask a lot of questions cause so many classes are required and the order is a bit not clear even with the prerequisites written out
don't be too shy to ask, and you'll be fine
ah
my seniors did a list / table / mindmap for those
you can construct one in case you dont have it when it's time to apply for classes
it's a good logic practice
Mindmap is like a tree I imagine?
yea
Yeah probably should do that
It will give me something to do
Alright see ya 👋 and thx
cya!
Guys, please me help with this VSCode problem. I don't know what to do.
You're asking on a Mathematics server
Well this isn't a help server, so don't expect anyone to know. Just ask on a discord server thats designed for programming, or better, VScode
Okay, fair enough.
the problem is using vscode at all
tbh
just use vim
and dont use language servers
what kinda of problem is it?
also u can use sublime text
just, vsc code nice, but insome specific situations its not the best editor
U need to edit your spacebar
Yes
The real axis is the x axis, imaginary is y axis. If you're thinking about complex numbers
like what if you alrdy plot the equation on its real x and y coordinates and now u need a imaginary axis idk
ok ig im just over complicating it for myself
(x^2+1)(x+1) =0
this has a real solution AND an imaginary solution right
yess
now
suppose you plot the rest of the equation too
yeah
where would u plot that
in the z axis?
but then what happens to x = -1 when y = 0
y is 0 in that example
equation is (x^2+1)(x+1) = y
ok
i dont have to but i still do🥲
fair enough
what's the most interesting conjecture you know of?
a b c
an already solved one or an open problem?
if you ask like that, both
whitehead problem
Pre-uni student here, can anyone explain me to me how complex numbers can exist in real life, want to know out of pure curiosity
Ask a physicist to explain quantum mechanics.
Do you know if complex numbers exist in any other fields outside of physics
Seems so hard to conceptualize imaginary numbers existing
I guess quantum computing is sort of a cs subject?
I think they’re used when working with electricity too
Im not sure if they’re needed for it or it’s just more useful to have them as a tool
do you also conceptualize why -4*-3 = 12?
If you accept that multiplication correpsonds to reflection, then you should also accept that complex numbers corresponds to defining a number system on the plane
can someone help me with this question. Expand and state your answer as a polynomial in standard form.(4x-y^(3))y^(2)
do you know how to expand+multiply?
nope
you should go to #❓how-to-get-help
but do you know how to expand 3x(x+y)
Sort of. My understanding of that is subtracting -4, 3 times which is 12
No clue what that means, but my main motivation for studying math as of now is to one day understand complex numbers, so hopefully I will soon
If you have the real numbers as a line with 0 being at the middle, then -1 is just the reflection of 1 through 0
Not sure if this helps
But why should multiplication by a negative be repeated substraction?
It's just arbitrary no?
in the same way, you can define a certain number system on the plane
which extends the number system defined on the line
well multiplication is just adding no, and I can re-write adding -3, -4 times as subtracting -4, 3 times
for example, what if you just forgot about complex numbers
and just thought about defining a number system on the plane
What then does multiplication represent?
a number system is a number line right
by number system i mean a field
i.e. one where you can do addition, multiplication, substraction, division
Well to be honest I would've just said addition/subtraction multiple times, but it seems that is not what you're getting at
i mean my point is this: it's actually somewhat arbitrary that someone decided multiplication by a negative number means repeated subtraction
you first define multiplication for positive numbers and say it means repeated addition...fine
oh I see what you're trying to say, if multiplication is adding, then negative multiplication is adding negative times which doesn't make sense, so we just decided it was repeated subtraction
yeah
now let's say you want to extend to a number system on the plane
if you represent everything using rectangular coordinates, it's not actually so clear what's going on.
Let's say you have rectangular coordinates and you want to define (a,b) x (c,d)
What is the geometric interpretation of (a,b)x(c,d) being defined to be equal to (ac,bd)?
and also, does it make it into a number system/field if you define it like this?
Because remember, you also want to define (a,b)+(c,d) = (a+c,b+d)
Which implies that the additive identity is (0,0) which means that anything else you should be able to divide by
But then... how do you divide by (1,0)?
so you immediately see that you can't define it like this if you want a number system
(1,0)*(0,1)=0 so zero has divisors therefore not a field
Of course now it's not at all obvious how to define multiplication. But interestingly, if you switch to polar coordinates, stuff becomes perhaps more clear
If you now think about how to define multiplication on (r_1,theta_1)x (r_2,theta_2)
you end up with (r_1r_2,theta_1+theta_2)
I'm not sure what you mean by geometric interpretation but I imagine it is the same thing, (a,b)x(c,d) is adding A c times on the x axis, and adding b d times on the y axis
well okay just forget about that point its not so important, the bigger point is that you cannot define a number system
Okay so what you're saying is, multiplication is sort of arbritrary and hence to try and understand complex numbers, you have to take this into consideration
to motivate this, we should have in rectangular coordinates (1,0)x(-1,0) = (-1,0)
Which translates to polar as (1,0)x(1,pi) = (1,pi)
wouldn't it be, theta1 * theta2
read what I replied to it
Well my objection to your objection about complex numbers seeming to not exist is that not everything in math neccessarily has some sort of physical interpretation
The example I gave being multiplication by negative number
Okay I see, just out of curiosity when did this idea come to maths, from my understanding, when imaginary numbers were first created, they were seen as literally imaginary and non-existing
yeah i disagree here
maybe not physical, but existing in reality
actually i can agree because a lot of concepts are too hard to make analogies with reality
at what point did we say, okay hold on, just because it doesn't have a physical interpretation it can still exist, was it when we started seeing complex numbers in real life equations or did this idea exist prior to it
not sure about the history of it all
maybe before math was invented @neat lintel
According to veritasium's video, complex numbers were introduced as a computational aid when solving polynomial equations
language gets pretty abstract too
i'm wondering if there was something specific we discovered that enabled us to say okay it doesn't need a physical interpreation to exist
i mean what is the physical interpretation of the quadratic equation?
trajectories
Right I'm speaking from that, in that video it mentioned when they were first introduced, people didn't believe they actually existed because there was no physical interpretation, hence at some point mathematicians changed ideas
fair
I believed they use geometry
though Im not familiar with how projectile motion is derived without calculus
even more generally polynomial equations can be representitive of a lot of things
There is this guy on youtube that you might find interesting @neat lintel nj wildberger or something
I'll definitely check him out, is he like a 3b1b type of guy
no he is a guy that likes to talk about how modern mathematics is wrong
that sounds awesome haha
no he is a professor
because the objects we use, namely real numbers, do not exist
Is there a specific video you'd recommend, skimming through his youtube channel, there's a lot to choose from
nj wildberger has very "non standard" views on things from what i remember
hes a finitist iirc
what's a finitist
for context,you probably want to first understand what a real number actually is
people who do not accept the existence of infinite objects
though im not sure if its strictly necessary to understand his viewpoint
yes he is very very outside of mainstream mathematics in that he is literally trying to make a new mathematics on his own
you dont know this
but the idea that real numbers actually don't exist, nonetheless are very convenient is quite interesting
and every mathematician wants to make new math
no I do know
Is this a popular mathematical academic take, or is it generally accepted by pretty much everyone that infinite objects do exist
he has content where he builds math up "rigorously" using his viewpoints
and he even sells it iirc
Most people don't even think about whether or not they should exist, they just use them
But the people who do think about these kinds of things generally accept them as existing yes
Otherwise things are very difficult
avoid cranks
.
lol
kids these days
Chmonkey
very active role is not controlled by the mods
thats what they said to me last time around as well
truly believe its an escape hatch 
You last messages were over 9 months ago so. not ver active
i am very actively promoting this server irl
That doesn't count sadly
I thought/assumed that the things we talk about in formal systems are confined to just the formal system. The interpretation of the formal system I assume can then be used to see if a different formal system can be interpreted in the same model?
And if you want to capture some idea it needs to be written in formal language, and all that captures is just the formal definition according to the formal system.
And natural language I assume doesn't have an exact mapping to formal language, so you don't know whether the idea expressed in natural language matches your formal definition or not.
I assume physics then is a bunch of models that are gathered by thinking about replicable measurements of what we perceive to be the external world, and then expressing these replicable properties in formal language? And then using what we know about formal language to talk about them?
i have a snippet from a book that is a hard counter to this argument
apparently i am not allowed to upload images 😢
Lame. U could post in chill and link to it here
i can do that but i want the mods to acknowledge my helpfulness and promote me to a greater being as well 
here you go
I've heard that there are philosophical problems with each philosophical interpretation of mathematics, but I don't understand how the picture is a counterargument? It seems to say that you should think about mathematics in terms of the formal definitions as written in formal language
the natural medium
I interpreted this as 'The formal language is the natural medium of mathematics.'
there is no natural medium outside of the formal language
it is as natural as it gets
I don't see how this is a counterargument?
my subscription for a working brain ends here, i cant help you anymore
back to my troller self
https://www.youtube.com/watch?v=GZgIYGaeWy0 don't be like this
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Wow the video was actually quite interesting
random numbers go
652336711325712386
69
Oh cool an Abstract Algebra study group starts up just when I started actively self teaching it 🙂
I should power through the last chapter of Understanding Analysis before it starts up
hey guys
hello
Hi
ded
dead is good
can any1 help me
Please read #❓how-to-get-help
Please read #❓how-to-get-help
Please read #❓how-to-get-help
yeah idk
is capital pi notation useful or can it be expressed with summation
I don’t think it’s used all that much tbh but I’m wondering
It is useful
It works the same way as the capital sigma notation
So it's not like you have to learn anything special with it
They are the same?
capital pi is multiplication and capital sigma is summation
i mean you can represent each in terms of the other (for real positive terms) but why would you want to
Ok that makes sense. I was just wondering if capital pi was easier to write in terms of a sum or if it’s good on its own
ofc
g
if you want to, for $x_k$ positive and real, see how you could turn $\prod_{k=0}^{\infty} x_k$ into $\sum_{k=0}^{\infty}y_k$, where each $y_k$ is real
\prod
valley
I don’t know how to otherwise I would try
I haven’t taken precalc so I haven’t used summation or natural log yet
Only practice problems with logarithm rules
no actual applications
i mean, that’s literally all you need though
I don’t even know where I’d begin. My first thoughts were using a tower of exponents or putting another summation inside of the first
idk how to do anything with e^ln(x) it means nothing to me
valley what exactly do you have in mind for this
y_0 = \prod x_k, y_n = 0 for n > 0
lol
||ln||
i want to know what final expression you have in mind
of course
is there a different way to do it 
maybe i just misunderstood what you originally meant by "turn into"
i read it as "make the product literally equal to the sum"
in your defense "turn into" is definitely not a very mathematical term
We plan to start today itself
Good book!
i forgot to fill it out before now but i just did
bro there's a latex bot? that's so coollllll
stop 💀
@cold needle please ban @wild comet this spammer from this server
@cursive token can I DM you about the abstract algebra group?
Feel free








