#serious-discussion
1 messages · Page 546 of 1
Lol
This was for whoever asked about differential galois theory by the way
yes (and as an unrelated note), it turns out that if a polynomial's derivative is irreducible in a field then the polynomial must be separable in said field
Do you have a reference or source you like for reading about differential galois theory?
damn differential algebra is so cool I wanna learn it so bad, but I need prereqs first 
Magid's lecture notes are good I think
there should be books too
I'm too busy with all the other math I'm doing, differential galois theory seems cool though
Hello, I would need someone who knows how to calculate the probabilities of winning or losing according to a percentage of success (I don't know if you understood me)

try reading #❓how-to-get-help first
Who tf came up with this colorscheme for a textbook cover
my beloved yellow books…
yamin over here taking a picture of his computer screen
Maybe it's the version for red-green colorblind folks? xD
imagine reading algebra by lang on the first go
literal death
What the fuck. This has to be edited in some way.
That’s actually an incredible book
Reading it currently
Although that may be a bootleg color scheme
I referenced it for exceptional aut of S_6
look. there he is. the man with the exceptional automorphism. I wonder what he's going to do this time. I sure hope it's not "mentioning the exceptional aut of S_6"
Guys, there's a math fight in help room 2. What do I do?
In the future DM modmail or ping mods in the channel, i'll look at it now
Ok
Yeah you only need to ping mods if it's like, vitriolic. An argument is fine
The snacks taste good
Is there a way to separate them into teams and then they can collaborate on their argument?
Lol
It's too messy rn
They will have to self-organize
form unions
better not be forming unions in my beautiful us of a
^Jeff Bezos
Hello! I'm not sure if this is the right channel for this, but I was wondering, do you guys think finding the surface area of a bean might be a good Math Internal assessment HL topic? I took inspiration from looking for the surface area of an egg and thought it would be similar in difficulty, and thus, good for a Math IA topic for next year, I'd really appreciate any perspectives on this🙏
I think so! You can attempt to generalize methods to other irregular surfaces as well if it turns out to be too simole
And this will give you some personal motivation points or however it's called
The yellow books look so good
anyone else enjoy just scrolling through latex documentation trying to guess at what the crazy notations could represent
i just wow at the cool symbols
lol
These are like unreadable
dope
my type of textbook
So,How does a normal PDE textbook look like?
Random equation -followed by just lines and lines of derivation?
Like this for example
yeah
pretty much
context and history for random equations
and then the rest
honestly its pretty aesthetic
sweet jesus
that textbook cover is actually genius, it forces you to open it so that you don't have to look at it, thereby encouraging you to study more
@nocturne tusk so do u wanna learn abt induction?
I suppose so
well like unless youre really interested theres no point in tryna learn it lol
sorry im having a big adhd moment rn
if there is something specific you want help with let us know
Ah
You were originally trying to prove the power rule right?
And someone recommended induction
yes
do you know the binomial theorem?
I know the basic stuff I think
like, do u know how to expand $(a+b)^n$
like (3+x^-1)^7 or smth
Ninja
do you want someone to help you prove it yourself or do you just want to see a proof of it?
proof for myself i think
ok so, can you expand this for me? do you know the formula
idk the official notation but I cam get something
yeah use whatever notation you want
$a^n+a^{n-1}\binom{n}{1}(b^1)+\cdots +a^0\binom{n}{n}(b^n)$
awful latex but I think its semi readable
Nice, that's correct
idk how to do column vectors lol
Ninja
Ah
there is a $\binom{n}{k}$ command
Lochverstärker
im gonna correct my thing just so it stops annoying me
Ninja
$\mqty(x \\ y \\ z)$
Nice
Is that a built-in thing or your own shortcut?
built in
💀
I've been using \bmatrix 
part of the physics package
katie <3
which is default in latex discord
ayyo good job
swag
You mean I didn't need to do \begin{pmatrix}x \\ y \\ z \end{pmatrix} this entire time? 
physics package 
Next, can you state the limit definition of the derivative?
do u know abt dv and pdv
also in the phys package
its based
Yeah \binom is best for the choice function
$\lim_{h\to 0}{\frac{f(x+h)-f(x)}{h}}$
im still used to and prefer $^nC_r$
Ninja
that looks weird
Ah yeah that works too
i have never seen this notation ever ninja
n choose r
that was the only notation i was taught in school
I've seen $_nC_k$
That I did know. I really should use the phys package in my regular TeXing.
in general i think you need good reasons to have superscripts before a symbol
this is fine
this isnt a good reason
Huh it looks right.
its not just fine, its correct
It irritates me
im not doing all of that using the first principle in latex
lol, just copy ur old latex and change it where needed
if you want write it on paper and send a picture i guess lol
$\lim_{h\to 0}{\frac{(x+h)^n-x^n}{h}}$
in car to glasgow
no this is not correct
lmao ok I didnt know that
let f(x) be xⁿ
wait no im stupid yeah

katie <3
ninja teacher arcs huh
im giving back to the community 


$\lim_{h\to 0}{x^{n-1}\binom{n}{1}+\cdots +x^0\binom{n}{n}(h^{n-1})}$
hope and pray
Well done
Nice
now we really wanna get rid of the h in the denominator, because if we apply the limit now we get 0/0 and thats indeterminate
so can you cancel it out?
As a side note, using the binomial formula you can prove that $\frac{d}{x^n}{dx}=nx^{n-1}$ but only for $n \in \mathbb{N}$. Iirc, if you want to prove it for all real powers you can use logarithmic (impicit) differentiation.
grass
cock
it's not \x
katie <3
Getting close!
yes!, now just apply the limit
$x^{n-1}\binom{n}{1}$
katie <3
and what is $\binom{n}{1}$?
feeds
$nx^{n-1}$
katie <3
yooooo
🥳

here is the whole proof for reference if you wanna look thru it

knowledge is power (rule)
You are now unstoppable

I watched a proof of the chain rule
I understood it, but like
how would they know to do that
1 sec ill find the proof
In this video we work through a proof of the chain rule. It's not a rigorous proof but it gets the point across and is definitely good enough, in my view, for a student just learning calculus! The proof doesn't really help you to use the chain rule but it's good to know there's some basis for what you do.
where does that second fraction come from 😭
what fraction
The transition btw the 1st and 2nd step is just a change of denominators
instead of h at the first fraction, its moved to the second one
$\frac{g(x+h)-g(x)}{g(x+h)-g(x)}$
katie <3
this fraction is just 1 lol
That just evaluates to 1
they multiplied by 1
ohh like how did they come up with it?
yeah
idk ¯\_(ツ)_/¯
lol
Normally it's just smart guesswork. In this case they want the first fraction to look like a derivative.
So getting a g(x + h) - g(x) in the denominator would make the first fraction in the form of a derivative.
But then since you can't randomly divide, you have to multiply, giving another fraction and rearranging it gives another derivative.
A lot of things feel like that yeah. 😂
you've never seen it before
you get better with practice
actually I think I owe myself a bit of lenience cuz like
I had 2 lessons on proof by deduction and exhaustion
one of which I missed
But really the first thing you "should" think of here would be that we want to use the limit definition of the derivative with $f(b) - f(a)$, where $b = g(x + h)$ and $a = g(x)$. But that requires the denominator to be $b - a$ so we needa multiply and divide by $b - a$.
PhenomPlasma
that is the only proof ive ever done
Proofs are definitely not easy when you first start.
I still find a lot of them hella hard.
i can confirm that i also find proofs hard
I had no idea where to start so I skipped it
Was it to prove there are infinitely many primes? That's usually the classic one they like to go through.
the mark scheme said I had to use exhaustion by representing prime numbers as (10n+1), (10n+3), (10n+7) & (10n+9)
i would have never fucking thought of that
A lot of math is like this.
There's a proof in Spivak's Calculus that pi is irrational and he just pulls these functions out of thin air.
Oof, I skipped that chapter 💀
hmm
I can hardly even do the first 5 questions on the first chapter
i dont think this is the original proof of irrationality
so in this case its also easier because you know the result
and then people just ask "can we prove this using wtv techniques"
and its a lot easier if you know where you want to end up
Ah yes I definitely would've come up with these functions.
what the fuck
what was the question exaclty?
to find all x that this is true for?
find x given ghat
That can't be solved without calculator I'm pretty sure.
yes
find interval for x
yeah thats what i was thinking too, prove its strictly increasing
I googled it and it was using some weird ass functions
then note f(1) = 4
Wait but if that's Spivak chapter 1 you wouldn't know calculus.
Still though I guess you would know from high school thst 3^x and x slope upwards.
idk if I have the exact question on my phone
Oh yeah Spivak Exercise 1.4(xii).
Up to now the only Spivak I've read is the pi chapter (I think 16). 
you dont need calculus to show this is strictly increasing
Honestly it's an interesting proof.
wait yeah, you just need to prove x > y implies f(x) > f(y)
Technically it doesn't ask you to prove it's correct so.
but wait
the only possible solution i could think of
no i dont get it nvm
was to plot both graphs and see the intersection
but idk it just dont seem right to me
3^(x+h) + (x+h) = 3^x *3^h + x+ h >= 3^x + x +h > 3^x + x for every h > 0 should work?
you just need some kind of argument that 3^h >= 1
and how do u do that?
Spivak defines exponentiation much later in the book so I don't think we're expected to show that
I don't think you need to be that rigorous at the start of Spivak to be honest.
I think it's probably just there to test your intuition or something.
ye hm
Yup
oh well I havent touched spivak since that question
💀
idek all of precalc yet
maybe you do need some continuity argument 
Is spivak a hard calc book or an easy analysis book
it is certainly a book
Definitely one of the books of all time
I think I still have some trig left to learn then I should be good for precalc
like radians + sec cosec and such
A calculus book that's proof based and more challenging than most
Its not really anal from what I have heard
i dread the day i have yo learn real analysis 
I'm dreading it and yet somehow slightly weirdly attracted to it.
finally doing more than just learning how to model the growth rate of a tree
im someone who doesn't really enjoy pure math
so thats why im kinda dreading it lol
I mean maybe you'll learn better models for the growth rate of the tree. 
if you study engineering you dont really have to do real analysis
I'm kinda in both camps. I like pure math a good amount but when it gets too abstract I tend to get a bit... lost.
tho that being said, I am only just starting year 13, so it's hardly advanced

yeah i mean, prolly not but like i still wanna learn like physics in my free time or maybe even as a career idk, but like for that i think havinh a good grasp of real anal is necessary
I hit stackexchange after being stuck for 15 minutes
ive heard many conflicting things
I only ask (here) after trying for a couple hours and running out of ideas. Imo you perhaps shld try to spend a bit more time finding a solution?
i feel like a lot of a real analysis class or just math classes in general maybe are focused on studying pathologies of the theory
Where I start struggling is when I have difficulty understanding the need of definitions. Like I can understand concepts like partial derivatives, eigenvalues, Jacobians, etc just fine, because I can attach it to some purpose. But when I have to define left cosets I'm just wondering OK how in the world is this gonna matter.
and an engineering student just doesnt care about that
and even in physics a lot of the pathologies dont appear
tho tbf i have a bad view of physics
after i learn like algebra and la and stuff
self studying is too hard I can only learn stuff from classes
but I only have 4 classes a week
and im missing 3 this week 😭
i dont think this will work out too well if you are dreading it
you should learn NT instead 
im mostly exaggerating btw
It's because maths is kinda taught backwards. We get told definitions as if someone one day suddenly came up with it and everything just worked. When in reality they messed around with stuff for a while and eventually were like "huh this thing I'm using is pretty handy i should probably call it something and study it a bit"
Oh lol I definitely do, I was exaggerating a bit
tbf a good class will motivate (most) definitions
my adhd doesn't let me work on something for more than 5 minutes if I dont get it instantly
like. its a lot of factors. one is that Im very bad at proofs, another is that like super abstract stuff that's also hard to understand is really hard for me to motivate myself to learn.
a lot of the ideas in ranal seem super interesting and i do wanna learn them and i do want to have a very solid understanding of math
im just worried im gonna suck at it and feel like a moron 
Everybody agrees real analysis is hard
So don't worry if it doesn't click with you instantly
being bad is the first step of becoming good
like ok the reason i really dread it is because i tried it once like a year ago and i almost cried because i couldnt do an epsilon delta proof 
I dont like people putting difficulty on things
I don't think anyone can do epsilon-delta the first time they see it. 😂
cuz like I often struggle with shit and people just go "this is easy lol"
Difficulty is pretty much always subjective.
read #❓how-to-get-help
help bro pls
it might literally just be that i associate ranal with those feelings now
Also chances are those ppl probably spent a lot of time on the subject before it “felt easy”
Is RA focused that much on epsilon-delta?
ofc, but that doesnt mean people should belittle because of that
It has quite a bit
Oh no that's not what I meant at all. I agree with you.
But there’s certainly other stuff involved too
I don't think you need it much after you use epsilon delta to proof some limit rules
Actually
It pops up here and there I’d say
Sometimes you do compute limit using epsilon delta
But at the same time I'm saying it's normal to think some stuff feels easy to you and some feels hard.
Yeah
epsilon delta is like
Yes
See that's what I thought.
you have to learn to walk before you can run
later your arguments are more intuitive
I flipped through an RA book and didn't actually see that much of it.
"ok so sending this guy to 0, this guy also goes to 0, so ..."
But yeah it’s often in the context of limits of some form or another
and epsilon delta is where i learned i didnt even know how to crawl 
I've tried understanding epsilon-delta so many times that it is intuitive to me now.
And there’s definitely a bunch of other stuff involved with RA yeah
Its good practice for when you go on to do analysis in more abstract spaces, where you really are going to need to use ε-δ for a lot of arguments
the thing is you need to be able to formally check your own work
so you have to know the definitions
later you can do "intuitive" arguments
idek what a limit is, I just assumed its like "as x approaches this number, the max/min value this function approaches is...."
but you need to learn to be self critical and be able to check your own arguments formally when needed
Later on you’ll also be able to be more flexible with the epsilons too
The actual definition is pretty much just writing out exactly what this means in terms of numbers.
because again, intuitive ideas dont always work
this was the part that made me wanna bang my head against a wall
i had no idea why my proofs were right or wrong. i had no idea how to check, when i had a wrong proof i looked over it for so long and couldn't find the mistake
and a real analysis class will spend considerable amount of time and showing you pathologies
is it like
so you understand that
the closer x is to y, the more accurate it becomes
its probably really difficult to self study ranal now that i think abt it
this is a thing that requires time and why i think purely self studying is not feasible for most
you need someone else to check your work and correct you, especially early on
later, you can do more things solo, but you still need sanity checks from peers
yeah. thing is i dont want a math major, but i still want to learn these things.
That we can make f(x) as close as we want to L (this is made rigorous by saying that we can make |f(x) - L| < e for every positive e), provided x is sufficiently close to a (made rigorous by saying there exists d such that |x - a| < d). I think that's essentially the definition of limit almost done.
This I’d say is a pretty big part of the difficulty tbh
where i am physics majors can just take the math classes that math majors do
same for engineering
ah yes... words...
It can be very hard at the start to know if what you’re doing is right
Epsilon delta is a useful tool for stuff
idk if this is possible for me but maybe ill look into it?
Yeah epsilon-delta helps when working in other settings too
only an hour till I am in Glasgow woo
i mean maybe i could try to find a way to study with people here
You could also ask for a proof check maybe
Need summer activities
In some of the channels
god i wish i had more free time now that its summer 
I need other people to make me study, but everyone I know will either not know enough or be way above my level
i realize i am shitposting on discord for an hour already
but i am actually editing while doing so!
i thought it was just la
But I just don't feel like doing analysis
and calc
If you want to do ML rigorously,you need analysis
you need to know analysis, yes

and then its a ton of numerics
I assume for like just doing ML you dont need that much right.
Tbh some of the numeric stuff I’ve come across feels like putting in actual numbers instead of an epsilon
quick unrelated question
Also MATLAB
what does advanced number theory consist of
numbers
Too broad
no way
it depends
Probably rings
just like
its like, number fields tho right
examples ig
and integrals
number fields is an example, yes
All I know is that it can get ultra hard
thats like the original starting point of modern NT
Well it uses galois theory ig
so uh katie
god everything in math uses everything else
you know how there is the complex number i
yes
originally NT studies the integers Z
an old question you may want to ask is which numbers can be written as the sum of two squares
really depends on the class
so x^2 + y^2
one thing you can notice that over the complex numbers this can be factored as (x+iy)(x-iy)
uhhhh
you could be doing the kolmogorov theorem on the convergence of the empirical distribution, or you could be like hurr durr F-test goes here
and this multiplicative way of writing this is much easier to study because we have a lot more tools
but there is no complex number i in the integers
so you can think of "just add it to the integers"
and this gives you numbers of the form a+bi where a and b are only allowed to be integers
now this turns out to behave somewhat like the regular integers
in stats there's some neat theory connecting estimators and tests, bayesian stuff etc, for describing "optimal" approaches
there's also a lot of measure-theoretic analysis
and you can define notions of what it means to be a prime number
and then there's the hard applications to actual data
im gonna be honest
Oh damn, analysis is everywhere
and in fact classifying how primes behave in this thing will answer the original question
and this leads to more general questions
i lost you at "multiplicative"
oh well
the multiplicative structure of the integers is in many ways nicer than the additive
you have for example the fundamental theorem of arithmetic
so every integers can be written uniquely as a product of primes
questions about representing some number as a sum are much harder
I'd argue that's very far from "nicer than the additive"
its just a vibe for now
I think
prime factorization yields an iso between N_>1 and N^infty
I need to learn stuff
the latter has much more space to miss
so you get much more "no" answers
to ask interesting questions about addition you have to start with fucked up sets
hence the hardness
and writing x^2 + y^2 = (x-iy)(y+iy) is kind of like a factorization
oh well, i care about arithmetical questions and writing things as products is nice, writing things as sums is not 
idk, weird argument
I need to find friends who are as dumb as me so I can talk to them without being incredibly confused
i tried 
I think I probably went a bit out of my depth asking about that
asking abt "advanced anything" will definitely sound like nonsense unless you already know a little abt it lol
i dont know, those things were studied before calculus was invented
albeit with different language and generality
but yeah no I should defo learn the basic shit beforehand
I must learn the quotient rule...
i actually love the sum of two squares question because its so simple (and looks kinda dumb) but can lead to a lot of rich mathematics
if you know the product and chain rule you can easily derive it
fuck the quotient rule, all my homies hate the quotient rule
I never remember the right order. 
I always use the quotient rule to differentiate 1/x to remember which term comes first. 
low d(high) - high d(low) over the square if what's below
Left dright minus right dleft
its a rhyme to help you remember, thats what i use
@leaden skiff 3b1b?
yes
Same
Why remember the quotient rule when you can successively use the product, power, and chain rule everytime
I'm pretty sure it's (u/v)' = (vu' - uv')/v² but I get paranoid.
so true
I just don't do derivatives much anymore.
When I was still in high school we rarely got straight differentiation questions because I think the teachers figured out it was too easy. Differentiation usually only appears as an application (optimization) problem.
what are you doing now?
Slowly waiting 2⅔ years for uni to start because I have mandatory military duties coming up. So I've just been reading 1st year uni textbooks.

Currently reading Lakins' The Tools of Mathematical Reasoning.
It's used at my uni for discrete math but its an intro to proofs book.
@deep mango I remember you saying that every convergent sequence is a Cauchy sequence in a metric space
It just struck me
How tf do you make sense of convergence without a metric?
What was that about wew
You define it in terms of open sets
I read cauchy and convergent the other way around at first
A sequence x_n converges to a point x if for every open set U containing x, there is an N so that x_n is in U whenever n > N.
This is the same thing as the usual definition of convergence in metric spaces.
yeah you use the funny neighbourhood def
That definition talks about being in open balls
pftftft balls 🤣
"x_n converges to x" means "x_n eventually stays in any neighborhood of x"
Although, I'll need to learn about non-metriciazable spaces before I fully understand why we need that definition
Coz I have no idea what those look like lel
Hello! I'm trying to further increase my skill of problem solving, do you guys know any resources / books that might help me achieve this? Thank you.
imagine doing the quotient rule
it's literally the product rule
and memorizing a whole new fkin algorithm is not worth it
sorry wew but i laughed at this
you apologize to wew even though your laughter is at my expense.
"the art and craft of problem solving" is pretty good
it's geared towards competition math
Thank you.
"by Paul Zeitz" ?
ye, probably
Wow. Must suck to be you.
No it's actually dope
I sincerely doubt that
idk slurp have u seen rycs hair
Oh shi you’re right

I have no idea what I just read
x_n is stalking x
so you are okay with being the butt of every joke
if i were you i wouldnt let that slide
thats just me though

Humor is transactional
I am an endless hoard of patience
Better to joke about me than about someone who has a chance of being hurt by it.
Haha ur profile pic is a bird ahahaha lol gottem
how much do i have to pay
You pay in reputation
good repsonse
Lol
And you have no idea what the price is a priori

I'm pretty good at one liners tbh
I love this comment.
I have been seeing those types of comments online now for some reason.
It’s always funny; that is just me tho.
I don't think the comment was very socially aware tbh
The comment was a joke.
I believe.
Instigating, is what I believe it’s called.
I see
It’s a popular trend online.
I mean instigating means trying to start a fight
Lol, yeah.
yea its been a thing forever
its just more popularized by ppl online now
Yeah, been seeing it online now. That why I decided to comment.
Can you please explain what it is?
Not sure why it became popular.
its exactly what u said
not much else
i like it
thats gross
🤑
Just to let one know, I wasn’t in supports for any fights. I thought it was funny since I have been noticing those comments for a while in funny contexts.
Oh you think that's a more accurate description of the vibes?
Discord is nice
Honestly it's changed a lot of people's lives for the better I think
Hot take

Definitely, I used it a lot in past and people helped me a lot.
Discord is the best place for talking if you have ADHD lol
Everyone talking over each other
No need to wait
So good
Chat rooms are kinda cool in that way where you can have multiple different conversations going on and it's mostly fine
Top reason I use discord is due to its simple layout. The contents is not too much unlike Reddit and twitter.
Oh I like having multiple conversations at once in the same channel
Lol
Maximize confusion
lemme add to the confusion
That I can do, not sure how I manage to do it.
I think there is bigger context to this.
What is the definition of minimal element here?
Yeah this is exactly local vs global
There being an element which is below every other element is a global minimal element
A local minimal element would be one so that there are no elements below it
I can give a concrete example
that would be appreciated
what's the difference between partial order and total order
And that's it
A total order has every element is comparable
In the example I gave that's not true
a is not comparable to b
anyway, the point in emma's example is that nothing is smaller than a (so a is minimal) but a is not smaller than every other element (it's incomparable with b)
standard example of a partial ordering that is not a total ordering: the collection of all subsets of a set, ordered by inclusion ($\subseteq$)
OurBelovedBungo
and we could interchange the roles of "a" and "b" in that sentence
and get the same fact
(i.e. a and b are both minimal)
oh ok
that makes sense but is confusingly complicated at the same time
I have a picture
I see
If I can find a pen
okay lol
There
though its worth noting that this example doesnt really apply to this case
the empty set is smaller than all sets
in this ordering
so it's both minimal and least
still a good example of a partial order though.
directed graph 
Yes
They are preorders
correct
The James Webb Space Telescope was damaged by micrometeoroid for the fifth time since it was launched. Debris strikes like these are expected, but this recent strike was larger than anticipated this early in its mission.
00:00 Webb hit by micrometeoroid
01:02 Are micrometeoroids dangerous?
02:13 This was larger than anticipated. Or tested for....

guys join vc
Okay so
I've seen PPL say that
You can't directly compare two complex numbers
Is taking the modulus (or magnitude) of both and then comparing them valid?
is i greater than 1?
Well its modulus is equal to 1
so?
Well we can't directly compare a complex number with a real
Complex is 2 dimensional while reals are 1 dimensional
what
the more informative version of this vague statement is that C does not admit an order that makes it an ordered field.
every real number can also be thought of as complex
They behave like two dimensional vectors* sorry
I see
the word "compare" here doesn't mean it in the colloquial sense if that's the confusion
you can cook up lots of "orders" if you just want to satisfy the properties an order should have (reflexivity, transitivity, antisymmetry)
For instance you could use what is called the dictionary order, and say that a+bi < c+di if either a < c (in the sense of real numbers) or a = c and b < d.
Ooh
but the point is that this order does not behave well with respect to the operations of multiplication and addition.
So there is some sort of limitation if I define an order for comparing such numbers
yes, to be precise you cannot pick an order such that the following two properties hold:
- z < w => z + c < w + c for any complex z,w,c.
- z > 0 and w > 0 => zw > 0.
True
you can think of these properties as saying that an order is "compatible" with addition and multiplication in your field respectively.
Thanks 👍
no worries
(By the way, it's an easy but worthwhile exercise to prove that no such order can exist. If you can't see why immediately, I suggest you think about it for a couple of minutes.)
I've been thinking about this for a while, and here's my conclusion:
- Complex numbers are not ordered fields, i.e., total orders cannot be imposed on this field:
Say we impose a total order ≤ on C, and assume C is an ordered field.
In any ordered field, the multiplicative identity is greater than the additive identity.
So, 0≤1
This implies i ≤ 0 ≤ 1 or 1 ≥ i ≥ 0. So i≤0 or i≥0
Taking i≤0,
In an ordered field, squares are always non-negative, i.e., 0 ≤ a² for any element a in the field. This is one of the properties of an ordered field.
Hence squaring both sides of i ≤ 0, we get -1 ≤ 0 => i² ≤ 0. This contradicts the property of ordered fields, hence contradicting our assumption.
Taking i≥0,
Implies -i ≤ 0
Implies (-i)² ≤ 0
Implies -1 ≤ 0,
which again contradicts the property of ordered fields.
- This also contradicts the axiom a.b ≤ c.b, where b is any non negative number.
Say 1+2i ≤ 1+3i (by comparing component by component)
Multiplying both sides by i (positive number)
We get -2+i ≤ -3+i
And -2 is not less than -3, contradicting this property.
Hence, a total order cannot be imposed on Complex Field. Partial orders like ≤ where:
a+bi ≤ c+di if a≤c; or bi≤di if a=b,
can be imposed, but have limitations.
Hence, no such total order exists.
Yep, you have the main idea. Squares are non-negative in an ordered field because for any x we either have x >= 0 or -x >= 0.
In either case we have x^2=x.x=(-x).(-x) as the product of two non-negative elements and hence non-negative.
But in C we have i^2 = -1 < 0. (This last inequality following from 0 < 1 => 0 + (-1) < 1 + (-1) for example.)
Thank you for giving me such a wonderful excercise 👍
no worries, glad you were able to get something out of it!
By the way, something you might find cool if you don't know it already:
The ONLY complete totally ordered field is the real numbers.
(Completeness here is the statement that any bounded set has a least upper bound. Don't worry too much about it if you haven't seen this property before, but roughly it means it doesn't have "holes" in it like the rationals do.)
oh that's a nice one
Ohh I see
👍
a bit tricky if you don't know the "idea" to the proof maybe
Oh yeah I wasn't suggesting this second thing as an exercise, it didn't sound like the kind of thing Pencil was studying. Just mentioned it as a strong/somewhat striking result along the lines of his initial question.
Good morning, fellow individuals on the Mathematics Discord Server.
Good morning moddy!
Ily!
Good morning
Hello, Slurp and Idris. How are you both doing today?
Excuse me Slurp, I do not seem to understand the meaning of "Ily." Is that a health condition?
That is a heart condition? I advise you to speak to your doctor as that is very serious.
So basically for my assignment they gave us a corpus of texts and there seems to be quite a few texts about porn
That seems to be very interesting. Please enlighten me about pornography.
Gmod stop acting like a fucking nerd
Excuse me, that is inappropriate behavior for this community.

what kinds of functions are there other than polynomial functions?
There are exponential and trigonometric functions, for example. These can be represented by infinitely long polynomials, but they look different.
umm like
function that connect every person to his biological father
that technically is a function too
though it isn't taht useful
In general functions are just sets of tuples / ordered pairs
So you could say ${ (1,1) }$ is a function
grass
In fact $\varnothing$ is a function
grass



$\varnothing$ maps to itself
Llama calculus
Doing pretty good! How are you doing
good, it was weird and not funny
like in text?
doing your complex impersonation?
yeah
shut up
I did it for a day a few days ago
can't do it again
lol
are buisnessmen supposed to be professional and formal?
In general a function is defined as a relation, which is a subset (or equal to) the Cartesian Product of the Domain and Co-domain, and both could be any algebraic structures (Vector Spaces, Rings, Groups or even Sets). If algebraic structures are involved, we take the Cartesian Product of the underlying sets of these algebraic structures.
You can define a function as whatever as you like. Let A = {1,2,3} and B = {Coca-Cola, Chips, Amogus
}
Their Cartesian Product is a set of all ordered-pairs (a,b) where a belongs to A and b belongs to B [just like on Cartesian graphs when you label points. Keep in mind (a,b) ≠ (b,a) since they're "ordered"]
A relation is what we call a function, though not all relations are functions. Relation is a set of ordered-pairs, a subset to A×B (Cartesian Product), where between a and b in an ordered pair, there exists a unique relation between them. Like a=b, a+b is even, and so on.
Here I'll define my relation R = A×B = {(a,b) | a = b}.
That's your function right there. For each a, there exists a b where (a,b) is in R and if (a,b) = (a,c), then b=c, which is true. These are the two conditions for a relation to be a function. R(a) = b, where b can be thought of as the "mapped output of a".
So R(3) = Amogus
So you can create any function you like under these conditions.
Apart from polynomial functions, you have constant function, dirac delta function, kronecker delta function, dirichlet function, absolute value function, transcendental functions (like sin(x), cos(x), log(x), e^x) and tons of others
i would feel like either of them implies the other
idk if formal -> professional; I can be formal and very rude, which wouldnt be professional
Not so sure about the converse
I feel like it depends on the setting
in which case they are not generally equivalent
Dirac delta is not a function
Also this definition of a function as a univalent total binary relation is, while correct, totally obtuse for someone who hasn't seen anything beyond polynomials
I was just doing it to fuck w y'all
Much better to define a function in the usual manner, as a mapping between sets
👍
How it is incorrect?
hes using hard words like also, this and is
Oh lol xd
@next schooner i need a new rat fact
psychologist moment
kinky
And an average cat can hold up to 2 minutes 43 seconds
@brittle socket @arctic grove @neat lintel theyre not exactly functions if one requires a function's data to include a domain & codomain
(as one should)

yeah, i guessed so
yes i did!
hence why i was confused
@arctic grove uh huh uh huh uh huh
Dami dont bully me!
that really is why i was confused

ur face is a bully

What do you guys think is more efficient 6.5 hours of sleep 7.5 or 5.5
its fine if the domain & codomain is clear from context, then all one has to do is describe the ordered pairs
Also does anyone have a good schedule app I wanna use my time better
its just that in these cases the domain & codomain werent stated
yeah
but here there was no context 😵💫
like to fill in the details of the 2nd example, the emptyset can be considered a function from the emptyset to any set

Yeah but btw $f: A \rightarrow \varnothing$ is not a valid function for nonempty A
grass
just as a side note
Pencil/Idris

certainly allowable, as is $f : A \to {\emptyset}$
OurBelovedBungo
yep
7.5
although for me it's probably close to 8.5
anything around 8 hour is good
What does “efficient” mean in this case?
Pretty sure teenagers are supposed to get between 8 and 10 hours of sleep
So if you meant “healthy” then none of those
yeah, but if not possible, at least 8 is fine

ofc
lol
but yeah u need at least that much sleep
and at no point in ur life do u not need that much sleep
5-6 hours is more than enough actually when you are in highschool

Wat
I hope you are trolling the troll

Sleep deprivation is not good
unfortunately it's normal for a lot of high schoolers
Yeah alas it is
In highschool my priority was usually to sleep really
But I know many of my classmates were sleep deprived (and understandably so)
For me I’d be willing to potentially do some hw or whatever badly if it meant I could get my proper sleep in
when should i be sleeping during the summer?
i sleep around 11:30-12 then wake up at around 9
I tend to just sleep at a reasonably regular time, say 11 pm to 8
That seems fine to me
I sleep at 12 am at wake up at 6:30 or sometimes at 6 am
one of my friends sleep at literally 8 pm then wake up at 4...
time for the grindset
he's like the model ideal student bro studies and does all of his homework the day its assigned and shit
im happy for him, his work paid off
he got into a very prestigious boarding school
people need less sleep the older they get
sooooo, checks out, grampa
5?!! You have that much time?
Yes
"Browsing Reddit and chatting on discord till 5 am" don't count as "stuff to do"
Wow Reddit? What are you, a loser?
I'm referring to you lel
I understand
I was referring to how you immediately jumped to Reddit
You were obviously projecting
I don't sleep at 5 am.
Ye, I found your account the other day lel
I sleep at midnight and just wake up at like 6
😮💨
yes I made an account so that people could see it if they wanted
since all i do is post on the big brother and survivor subreddits
and give ridiculous takes about reality television
Ryc stands for reddit yuser cringe



infants needs a lot more
and sleep times go down with age in general
this is the better image
Get rkt

its still around 8
fairly close to it
it didnt get to 5 hours
ye
there are some people that can do with 5 hours
there is some genetic predisposition
but its not the norm
.
thats rather rare
i mean this is still true
those people can get rem sleep quickly
sleep required goes down
but not to 5 hours
there is also thing thing that if you sleep more often, you need less sleep
true
the general ideas is that the deciding factor is REM sleep, not time spent asleep
and if you sleep more often, you get more REM sleep
Ye, but that's not what I said lel

yeah, ik
Ok, maybe when I was messing with ryc
thats what i was talking about!
wait where is he
oh ok
my grandma be like
she sleeps like 10 pm - 3 am
literally
meanwhile I sleep 3 am - 10 am
and I am still tired af
my body needs like 9 hours of sleep
I was sleeping well at the start of summer but my dad kept getting mad I slept until 11 am
actually now I wake up at like 9 am
I keep trying to sleep earlier but I can't



