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/sci/ - Science & Math


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9670231 No.9670231 [Reply] [Original]

talk maths

prev >>9657809

>> No.9670270
File: 143 KB, 720x540, sys_archi_final.png [View same] [iqdb] [saucenao] [google]
9670270

>>9670231
私は、彼があることを書いたものを変数ではない午前:私は

"Please post in English." Don't new 4chan mods already understand the crypto backchannel shit already? Simon is advertising as a 'prime occupant node' so we know when to inject him and whatever.

>> No.9670271

為榮譽而先祖的I

為榮譽而先祖實力格局

>> No.9670273

For honor of ancestral strength. No Chinese dynasty can or will surpass. Many tales of epic legend to be told, many wish to bicker over their 'languages'. (sigh).

>> No.9670276

我有很大的能力,任何公共話語希望服務

>> No.9670803

Suppose I have a polynomial [math]F(X,Y)[/math] and suppose I do a linear transformation on the coordinates to get [math]F(X+Y,X)[/math] for example. Does [math]\frac{\partial}{\partial X}F(X+Y,X)[/math] mean the derivative with respect to the first coordinate or does it mean [math]\frac{\partial}{\partial X}F(X+Y,X)=\frac{\partial}{\partial (X+Y)}F(X+Y,X)\frac{\partial}{\partial X}(X+Y)+\frac{\partial}{\partial X}F(X+Y,X)\frac{\partial}{\partial X}X[/math]

>> No.9670856

>>9670803
>/1
I'd assume that d/dx ( F(X+Y,X) would derivate F just on X and not on the first coordinate, you could have used d1 (F(X+Y,X) ) to precise that. Plus you did a change to get a F°(X,Y) = F(X+Y,X) ; then you prob wanted to do d/dX (F°(X,Y)) and wrote it back on the form d/dX(F(X+Y,X)). Your X even if a dummy variable should refer to "the same X" in both expressions.

>> No.9671072

>>9670856
thanks for the response but not gonna lie dude, i have no clue what youre saying

>> No.9671410
File: 13 KB, 260x260, sadpanda.jpg [View same] [iqdb] [saucenao] [google]
9671410

I'm trying to draw contours with Octave, but I'm having no luck at all.
It works out with a simple

x = 1:2;
y = x;
z = x' * y;
contour(x, y, z);

but I'm having no luck with something like

a = -2.5; b = 0.5;
c = -1.5; d = 1.5;
x = linspace(a,b,1000);
y = linspace(c,d,1000);
[X,Y] = meshgrid(x,y);
Z = complex(X,Y);
region = abs(1 + Z) < 1;
contour(x, y, region);

>> No.9671618
File: 381 KB, 1080x1080, 1518823207765.jpg [View same] [iqdb] [saucenao] [google]
9671618

>>9670231
I need an honest answer lads. Realistically how long would it take me to learn Math (not CS) Linear Algebra? Is it possible to learn it in 2 weeks?

>> No.9671680

>>9670231
He is so dreamy.

>> No.9671771

>>9671618
If you are really smart and can just read the textbook and answer all the question correctly, 8 hours a day for 2 weeks would be enough. If you’re average/brainlet like me and have to take notes on the textbook and read it multiple times, 12-13 hours a day for 2 weeks is my guess.

>> No.9671778

>>9671410
Well your second code would just be a binary mask, no? 'region' is a true/false boolean array, are you sure contour can deal with that?There's not a lot of contours to be drawn when you have only two values.

>> No.9671789

>>9671410
>Octave
Why aren't you using matlab faggot?

>> No.9671793

>>9671789
>faggot
Why the homophobia?

>> No.9671795

>>9671410
>region = abs(1 + Z) < 1;
>abs(1 + Z) < 1
> < 1

You get region identically equal to logical zero with that.

>> No.9671797
File: 1.02 MB, 1470x992, The difference.png [View same] [iqdb] [saucenao] [google]
9671797

>>9671793
We need more babies. Choose to be normal.

>> No.9671802

>>9671795
>You get region identically equal to logical zero with that.
Why?

>> No.9671806

>>9671778
I need to look into it more then.

>>9671789
Because Octave is free?

>>9671795
Complex numbers my guy. Just let z = -1 + 0.5i.

>> No.9671811

>>9671806
You just need a cast

region = double(abs(1 + Z) < 1);

>> No.9671816
File: 240 KB, 1600x1200, Fast and Fourier.jpg [View same] [iqdb] [saucenao] [google]
9671816

>>9671811
Based anon, if I had a sister then I would have invited you to my house to fuck her.

>> No.9671840

Can somebody post the wierd math phd done by some american black woman wvmhich was nonsense?

>> No.9671844

>>9671840
http://www.theliberatedmathematician.com/wp-content/uploads/2015/11/PiperThesisPostPrint.pdf

>> No.9671848

>>9671844
This is embarrassing

>> No.9671850

Has anything interesting been proven using the concept of a metric space?

>> No.9671860 [DELETED] 

>>9671848
Indeed it is. Yet another reason why academic activities should be reserved for white (non-brown eyes) men.

>> No.9671867

>>9671850
Yes.
What a dumb question

>> No.9671870

>>9671867

Like what

>> No.9671872

>>9671870
Results related to metrizable spaces.

>> No.9671882

Is it true that algebraic topology is not completely rigorous by reasonable standards

>> No.9671914

>>9671882
It can be very rigorous if you want to take the time, but often it is unnecessary.

>> No.9671918
File: 47 KB, 1280x720, ricci_tensor.jpg [View same] [iqdb] [saucenao] [google]
9671918

>>9671618
Who is she? It depends on the level you wish to get. Assuming you refer to plebs linear algebra and that you had no exposure so far, I say it then it will take longer than that. You will need time to do exercises, and you can read all the theory in two weeks but you probably won't have a good knowledge (here I'm projecting the old me on you). Still it is a start.

>>9671882
What at are you referring to? To me it looks quite fine, you can think of stuff in a non-rigorous way (that's what you call an idea), and if it is correct then you can prove it.

>> No.9671939

>>9671882
>Is it true that algebraic topology is not completely rigorous by reasonable standards
Most of mathematics is not completely rigorous since the majority of published proofs are written in a way that resemble 'weak heuristics' rather then something actually rigorous (i.e. done in Coq).

>> No.9671978

>>9671844
Thanks

>> No.9672003

Hey /sci/
I been taking AP Calc BC this year, and during the calculus 1 section, i was doing horrible(getting D's), but now that i am in the calculus 2 section and reviewing for the AP exam, now everything that i found to be hard is suddenly clicking like what the fuck..
What happened /sci/?? Now I'm feeling confident about getting a 4 or even a 5 on the AP exam.

>> No.9672070

>>9671618
A lifetime

>> No.9672076

>>9672003
You learnt the material.
Take something harder.

>> No.9672078

>>9672003
What sort of answer do you expect? That lord xenu gave you his blessing?

>> No.9672087

>>9672003
high school calculus is basic bitch shit. they curve tremendously and ask extremely easy problems. i took calc 3 with a guy who was fresh out of high school after passing AB/BC or whatever the fuck you call it. up to calc 2. dude dropped out.

>> No.9672374

He looks half-white

>> No.9672697

>>9672003
Most things that are hard as fuck for a given person suddenly unravels after crying and working at it for enough time. Also AP is shit.

>> No.9672739

Homomorphisms have to map elements of order n to elements order at least n right?

>> No.9672746

>>9672739
At most n. You have f(g^n)=f(g)^n=e.

>> No.9672750

Stop posting Mochisuka. He is done.

See notes on his corollary 3.12 (if I remember correctly. Anayway, it is findable)

>> No.9672823

Hey guys, random old time lurker from non-sci boards. I have a question about identifying mathematician...

Long time ago on /sci/ I saw a biopgraphy post about mathematician. Right now I don't remember who he was, but I would like to read more about him. Things that I remember:

- Asian guy (probably Korean or Japanese)
- Might be dead or ~65 years old
- Might have moved to USA
- Doesn't play video games. In that bio he said that when being a kid he used to play console video games, probably had some addiction problems. I even now he has to force himself to stay away from video games.

Thanks!

>> No.9672847

>>9672823
Any specifics? Your description fits approximately two million individuals.

>> No.9672938

>>9671844
Reminds me of this pdf someone sent to our entire department.
https://www.docdroid.net/Q4MtogK/new-mathematics-and-new-physics-exonic-theory.pdf

>> No.9672977

>>9671410
>>9671778
>>9671789
>>9671795
Refer to >>>/g/.

>> No.9673167

>>9672750
>Stop posting Mochisuka. He is done.
>See notes on his corollary 3.12 (if I remember correctly. Anayway, it is findable)
What do you mean?

>> No.9673174

>>9672823
>65 years old
>as a kid he played console video games


Pick one you absolute fking idiot

>> No.9673450
File: 51 KB, 720x576, 1495497440241.jpg [View same] [iqdb] [saucenao] [google]
9673450

>>9672070
you

>> No.9673463

>>9672746
but that just shows g is in the kernel of f. how do we know f^n is the identity?

>> No.9673482

>>9673463
>but that just shows g is in the kernel of f.
No, it shows g^n is in the kernel of f, and that f(g) has order dividing n, and hence has order at most n.

>> No.9673512

>>9673482
i see thanks.

what about backwards. if the image g under f has order n, does g have order n? i feel like it does

>> No.9673540

>>9673512
>if the image g under f has order n, does g have order n?
No, try to come up with a counterexample (there are many).

>> No.9673571
File: 69 KB, 1077x445, IMG_20180415_183805.jpg [View same] [iqdb] [saucenao] [google]
9673571

How do I do evaluate the integral in question 4 with greens theorem? It just cancels out and gives me 0

I feel like such a fucking brainlet

>> No.9673613

www.youtube.com/watch?v=TCcSZEL_3CQ
> Socratica
What the fuck is that? She is hot, but her brainlet arguments talking is ruining everything.

>> No.9673637

>>9673512
Take any permutation group and apply the sign homomorphism.

>> No.9674092

>>9673167
There was some discussion on a blog post recently where it was brought up that the proof of his fundamental theorem (from which he derives ABC) is literally just
>interpret the previous discussion in the correct context (context not given), and the result follows
When asked for additional clarification he just tells people to reread the preceding 200+ pages

>> No.9674107

>tfw grinding for exams all day has completely drained my desire to do math
I miss freshman year when you could get a 95 just from showing up to the test

>> No.9674114

>>9674107
>implying good scores don't get easier when you ascend from babby stuff to big boy stuff

>> No.9674121
File: 31 KB, 654x351, Capture.jpg [View same] [iqdb] [saucenao] [google]
9674121

>>9674092
There are some details included in http://www.kurims.kyoto-u.ac.jp/~motizuki/2018-02-02%20Tan%20---%20Introduction%20to%20inter-universal%20Teichmuller%20theory%20(slides).pdf (slides 49-51)

>> No.9674174

Are there any non-academia fields of research that someone in the applied track can get into? I really want to do research but I can not become a professor I would be doing my students a disservice.

Also I know it's not really research but Operational Research in the military sounds really cool but I have a feeling that it might not end up being what I expected.

>> No.9674228

>>9674174
Wrong place to ask. Try >>>/adv/ or >>>/sci/sqt/.

>> No.9674263

>>9674121
and ....?

>> No.9674282

>>9674228
You're right. Sorry.

>> No.9674297

>>9671816
That's not Euler, but Frederick, the Great, from Prussia.

>> No.9674298

>>9674263
What additional clarification is needed?

>> No.9674311
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9674311

>>9673571
Brainlets off my board

>> No.9674603

Kill me I'm shit.

>> No.9674611

>>9674603
You and I both know that isn't true.

>> No.9674615
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9674615

https://arxiv.org/pdf/1804.04700.pdf
>The admissible domain of the non-trivial zeros of the Riemann zeta function
> Yuri Heymann
>In the present study we used the Dirichlet eta function as an extension of the Riemann zeta function in the strip Re(s) in ]0, 1[. We then determined the domain of admissible complex zeros of the Riemann zeta function in this strip using minimal constraints and alternative series of power functions. While proving the uniqueness of the line Re(s) = 1/2 in the strip Re(s) in ]0, 1[, we obtained the value of the Dirichlet eta function evaluated at the point s = 1/2 which was fortuitous. We also checked for zeros outside this strip. We found that the admissible domain of complex zeros excluding the trivial zeros is the critical line given by Re(s) = 1/2 as stated in the Riemann hypothesis.

>> No.9674640

>>9674615
>]0, 1[
as good as bad

>> No.9674706
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9674706

>>9674615
>Keywords Riemann zeta hypothesis

>> No.9674751

>>9674640
I fucking hate this notation so much. It's a minor thing but it's the ugliest shit ever

>> No.9674753

>>9674751
>I fucking hate this notation so much.
Mathematicians use "we", not "I".

>> No.9674761

>>9674753
but I'm an engineer

>> No.9674810

>>9674753
notatweon?

>> No.9675018

>>9674615
>https://www.scottaaronson.com/blog/?p=304
6-10 are definitely apparent here. Nothing is going to come of this paper.

>> No.9675055

How do you decide what programming language to use for a given task?

>> No.9675155

>>9674298
Where is the legit proof of that Corollary 3.12?

>> No.9675158

>>9675155
see >>9674121

>> No.9675164

>>9675158
> some details
> presentation
You do know what a legit proof is do you?

>> No.9675168

>>9675164
For what reason can a proof not be included in a presentation?

>> No.9675173

>>9675168
Some details is not a proof.

And also where is a reference to that Corollary?

>> No.9675176

>>9675173
>Some details is not a proof.
What's missing?

>And also where is a reference to that Corollary?
What do you mean? The statement of the main theorem in Tan's presentation is the statement of the corollary in Mochizuki's paper.

>> No.9675222

>>9674311

Thank you, though I am not memeing when I say I had that written on my page after looking up what to do online and learning about the closing the loop stuff.

But is this stuff meant to be intuitive? I can't imagine greens theorem irl.

>> No.9675306

>having a durry after an exam you know you nailed

good feel

who else /degenerate smoker/ here

>> No.9675344

Is there an easy elementary way to prove you cannot express (4)^(1/3) in the form
a + b*(2)^(1/3)
for a and b rational? I'm supposed to "decide" that reals of this form aren't an integral domain, but I can't figure out a way to be rigorous about it.

>> No.9675397

Good morning brainlets. I have the following question for you: consider a smooth zero mean function [math] u \in C^\infty(\mathbb{T}^d)[/math], (i.e. [math] \int_{\mathbb{T}^d} u(x) \ dx = 0[/math]. We know that (here [math]\mathbb{T}_n^d[/math] denotes the discretization of the torus with [math]n^d[/math] gridpoints):
[eqn] \frac{1}{n^d} \sum_{z\in\mathbb{T}_n^d} u(z) \to \int_{\mathbb{T}^d} u(x) \ dx = 0. [/eqn]
Now can we say something similar for
[eqn] \sum_{z\in\mathbb{T}_n^d} u(z) \to 0 ?[/eqn]
At first sight I'd say no, on the other hand, [math]u[/math] is a mean zero function, so things might cancel out once we take a lot grid points in each direction. For numerical simulation it at least works.

>> No.9676444
File: 186 KB, 1184x1184, em1512881149076.jpg [View same] [iqdb] [saucenao] [google]
9676444

This was just uploaded. I remember you like her.

https://youtu.be/8xWZpec9pwM

>> No.9676469
File: 147 KB, 633x645, TRINITY__GOKU.jpg [View same] [iqdb] [saucenao] [google]
9676469

'member that time I was the best mathematician and the best physicist and the science sluts still preferred to suck the other guy's dick?

Quantum Gravity
http://vixra.org/abs/1506.0055

On The Riemann Zeta Function
http://vixra.org/abs/1703.0073

The General Relevance of the Modified Cosmological Model
MIRROR 1: http://vixra.org/abs/1712.0598
MIRROR 2: http://2occatl.net/1712.0598v2.pdf
MIRROR 3: https://drive.google.com/file/d/1sXrFZhMo9OjoauL0SgAvpSxD_8qaAYi0/view?usp=sharing

>> No.9676501

>>9676444
Is there a single physishit here who doesn't happen to be an obnoxious avatarfag? I'm wondering whether or not their desire to study physics is caused by this disease or if it's the other way around.

>> No.9676572
File: 587 KB, 1280x1920, cedric villani&#039;s summer.jpg [View same] [iqdb] [saucenao] [google]
9676572

They are throwing old books out of the library, so I grabbed 11. Tomorrow I'll see if I can find more nice books.

>> No.9676647

>>9675344
nigga 4^1/3=(2^2)^(1/3)=2^1/3 x 2^1/3 and it is easy to show that 2^1/3 is not rational

>> No.9676774

>>9675344
you gotta ask yourself what's the minimal polynomial

>> No.9676795

>>9675344
>I'm supposed to "decide" that reals of this form aren't an integral domain
All fields are integral domains.

>> No.9676877

>>9676795
Assuming the axiom of choice.

>> No.9676880

>>9676877
We do not assume such things.

>> No.9676882

>>9671797
Not an argument.

>> No.9676883

>>9676877
Get a job.

>> No.9676925

>>9676880
Why not?
>>9676883
What are you trying to say with this post?

>> No.9676928

>>9676647
yes it is obvious that 4^(1/3) is not rational however so is b*2^(1/3), and the sum of a rational and irrational can clearly be irrational.
The problem is actually equivalent to showing a*2^(1/3)+b*4^(1/3) is irrational for all a,b rational and nonzero
>>9676774
not in the scope of the course. that's the thing, I have a feeling it's not at all easy to show and the author just wants me to guess.
>>9676795
that's why I'm just inclined to show it's not an integral domain

>> No.9676934

>>9676795
*actually just showing it's not a ring here

>> No.9676935

>>9671618
you can get a cheap dover book on computations for LA and finish it in 2 weeks ez

or you can be a grown man and allow for a bit longer. it may be possible to finish something like Valenza's text in 2 weeks if you're smart AND relatively mathematically mature, but I doubt you are else you'd have this solved already

>> No.9676938

>>9676928
Are you assuming choice or not? It's consistent with ZF that every non-trivial ring is an integral domain, and the ring in question is clearly non-trivial.
>>9676934
It's certainly a ring.

>> No.9676941

>>9676925
>Why not?
There is no reason to.

>> No.9676943

>>9676934
>*actually just showing it's not a ring here
All fields are rings.

>> No.9676957

>>9676925
Nobody with a job can shitpost as much as you do. Especially not any americunt, since your jobs are literal slavery.

>> No.9676958 [DELETED] 

>>9676938
to be clear I'm considering the form
a+b*(2)^(1/3), a,b rational
in the real numbers
it's not a ring because it's not closed wrt multiplication

>> No.9676977

>>9676957
Why are you assuming that I'm an americunt? Why are you assuming that I'm shitposting? Why are you assuming that I have no job?
>>9676958
>it's not closed wrt multiplication
This statement is independent of ZF by a rather intuitive result of Kripke. Which is why I'm asking if you're assuming choice.

>> No.9676981

>>9676977
>Why are you assuming that I'm an americunt?
I can sense your genetic inferiority.
>Why are you assuming that I'm shitposting?
Nobody can be that stupid unironically.
>Why are you assuming that I have no job?
See >>9676957

>> No.9676990

>>9676981
I actually have pretty good genes so you are mistaken. And why are you calling me stupid? Merely for not knowing what assumptions the people I'm trying to help are making? I guess everyone without mind reading skills is stupid then.

>> No.9676991
File: 2.42 MB, 320x240, 1462228321315.gif [View same] [iqdb] [saucenao] [google]
9676991

>>9676957
>>>9676925
>Nobody with a job can shitpost as much as you do. Especially not any americunt, since your jobs are literal slavery.
Not him, not americunt, but don't they have an easier life with respect to Europe? Slavery?

>> No.9676993 [DELETED] 

>>9676990
there's a bunch of friendly, like-minded people having a good conversation and you show up and try to soak up all the attention and derail the conversation. are you a woman?

>> No.9676999

>>9676990
If you have good genetics, please provide a photo of your blue eyes and blond hair. If you are seriously thinking that fields are integral domains only when you have assumed the axiom of choice, you are an idiot. Since I know you don't really believe that, and that you will not be able to give me that photo, I suggest you do what you lower life forms should do, and that is to serve us with good genetics.

>>9676991
No, unless you are trying to avoid the boredom resulting from too much free time. They are nothing but deformed mutts with tongues brown after licking their bosses' buttholes in order to desperately try to keep their jobs. Pathetic.

>> No.9677008

>>9676993
How am I derailing a conversation by trying to answer a question? You seem to be a woman yourself since you're getting this emotional over a mere attempt to help.

>>9676999
>please provide a photo
I don't believe in providing photos of my own self on image boards, sorry.
>If you are seriously thinking that fields are integral domains only when you have assumed the axiom of choice
Not "only when", it's just a possibility. You can always assume something even stronger or slightly weaker.
It's just that the statement "there exists a field which is not an integral domain" is consistent with ZF. You have to at least require that every non-trivial ring has a non-empty spectrum for every field to be an integral domain.

>> No.9677010
File: 6 KB, 751x143, constraints.png [View same] [iqdb] [saucenao] [google]
9677010

Can someone help me solve this system of linear equations for x and P? I want to say there is programming error, but I'd like some confirmation first.

I keep getting that x = 1.1 but x has to be between 0 and 1.

>> No.9677012

>>9677008
No. You simply assume a zero divisor has an inverse and reach a contradiction. Then you conclude that you can't have zero divisors in a field. Your shitposting is even weaker than usually.

>> No.9677028

>>9677012
This doesn't work unless your ring is non-trivial and has at least one prime ideal. This is strictly weaker than AC, but it's still necessary to prove what you're trying to prove.

>> No.9677034

>>9677028
No it is not. You require that the ring has a non-zero unit element, and that every non-zero element has a multiplicative inverse. Can you even define a ring's spectrum?

>> No.9677040

>>9676928
you can still sort of take the idea of the minimal polynomial
because an equation 4^(1/3)+b2^(1/3)+c shows that 2^(1/3) is a root of x^2+bx+c, but we know the roots of such a polynomial by the quadratic formula
it is easy to show that cubing a+b*sqrt(something) can not equal 2

>> No.9677054

>>9677034
Your proof doesn't make sense without the stated assumptions unless you're working in some weird paraconsistent logic. In which case you should state which definition of "field" you're using.
>Can you even define a ring's spectrum?
Classically (assuming every non-trivial ring has a prime ideal) the correct definition of the spectrum of a ring is given by constructing the right adjoint of the global sections functor.

>> No.9677060

>>9677054
I gave you the definition of a field. There are no inconsistencies in my proof.
>the right adjoint of the global sections functor
Explain in your own words what this means. I doubt you can do that.

>> No.9677092

>>9677060
>There are no inconsistencies in my proof.
I'm not claiming that anything is wrong with the proof under sufficient assumptions (which you haven't made).
>Explain in your own words what this means.
Assuming classical logic with modus ponens and that every non-trivial ring has a prime ideal (and the axiom of choice for good measure) and given the usual definition of locally ringed spaces define a functor [math]\Gamma : \mathbf{LRS} \to \mathbf{CRing}^{op}[/math] by [math]\Gamma(X, \mathcal{O}_X) = \mathcal{O}_X(X)[/math] with the obvious action on arrows. It can be shown that this functor has a right adjoint [math]\operatorname{Spec} : \mathbf{CRing}^{op} \to \mathbf{LRS}[/math]. Then the spectrum of a ring is anything in the essential image of [math]\operatorname{Spec}[/math].

>> No.9677112

>>9677092
Suppose [math]k[/math] is a field, and let [math]0\neq a\in k[/math] be a zero-divisor. Let [math]b, c\in k\setminus \{ 0\}[/math] be such that [math]ab=1[/math] and [math]ca=0[/math]. Now [math]c=c(ab)=(ca)b=0[/math], which is a contradiction, so [math]k[/math] can not contain zero divisors. You don't need to assume classical logic if you assume the axiom of choice, btw.

>> No.9677118

>>9677008
>every non-trivial ring has a non-empty spectrum
This is only true if you assume it to be true.

>> No.9677142

>>9677112
Your proof only works (although there will still be some gaps) if you assume that every field is a local ring and thus that every field is non-trivial, which is independent of ZF.
>You don't need to assume classical logic if you assume the axiom of choice, btw.
I know, but that way my proof is easily modified if the axiom of choice turns out to be unnecessary.

>>9677118
How so?

>> No.9677153

>>9677142
>trivial field
no such thing

>> No.9677155

>>9677142
Every field is a local ring.

>> No.9677156

>>9677040
I guess easy is all relative, I don't see how to prove that a+sqrt(b) cannot equal 2^(1/3) either.

>> No.9677157

>>9677153
>>9677155
You need at least some form of AC to prove this.

>> No.9677159

>>9677156
cube it

>> No.9677166

>>9677157
No. It follows from the fact that every field has exactly two ideals, one of which is the field itself. Thus the only proper ideal is also the only maximal ideal.

>> No.9677170

>>9677166
Which is provable if and only if every field is a local ring in the usual sense.

>> No.9677175

>>9677170
No. It does not require that assumption, but only that you pick a non-zero element in a non-trivial ideal and multiply that by its multiplicative inverse. Then you have 1 in your ideal, and it is then the whole field. Since this happens for every non-trivial ideal, there can be only two ideals in total.

>> No.9677176

why is it called riemann's hypothesis instead of riemann's conjecture?

>> No.9677178

>>9677153
>no such thing
Z/2Z is the trivial field.

>> No.9677183

>>9677157
>You need at least some form of AC to prove this.
How so?

>> No.9677190

>>9677175
You have implicitly assumed that every field is non-trivial which is equivalent to every field being a local ring.
>>9677183
Every non-trivial ring having a non-empty spectrum is considered a weak form of AC. And this assumption suffices.

>> No.9677193

>>9677190
>Every non-trivial ring having a non-empty spectrum is considered a weak form of AC.
By whom?

>> No.9677195

>>9677193
By mathematicians at large.

>> No.9677197

>>9677190
Every field is non-trivial. They are also defined as rings such that the monoid given by the multiplication and the set of non-zero elements is a group. You can't have empty groups, so there must be non-zero elements.

>> No.9677198

>>9677190
>trivial statement about fields
>somehow a non-trivial statement about every ring

>> No.9677199

>>9677195
>mathematicians
This is not well-defined.

>> No.9677202

>>9677159
yeah but then you get
2 = (a+sqrt(b))^3 = (a^3+3ab) + (3a^2+b)*sqrt(b)
and sqrt(b) is not in general irrational...
sorry if I'm missing something really obvious, but I can't see it

>> No.9677203

>>9677195
>By mathematicians at large.
This is false.

>> No.9677204

Help I don't understand colimits in category theory.

>> No.9677206

>>9677202
if its irrational then 2 is irrational
if its not irrational then 2 has a rational cube root

>> No.9677207

>>9677204
do you understand limits?

>> No.9677209

>>9677197
>Every field is non-trivial.
Intuitively speaking, yes. But to actually prove it you need at least some weak choice principles.
>You can't have empty groups
Only if you insist that every group be pointed. Tthis is a non-trivial assumption in ZF.

>>9677198
It is only trivial if you assume that every field is a local ring. And the statement "every field is non-trivial" is clearly weaker than "every non-trivial ring has a non-empty spectrum", but the latter implies the former.

>> No.9677215

>>9677204
Have you tried to approach them via simple examples? Try to see examples of direct limits and generalize those, since direct limits are a special case of colimits.

>>9677209
No. That is simply the definition of a group. One of the axioms requires an identity element.

>> No.9677222

>>9677206
ohhhh
thank you so much, I'm not used to thinking about this stuff at all

>> No.9677223

>>9677215
The definition of a group only requires the existence of a local point, which may very well turn out to be trivial without extra assumptions on the group. Showing that every non-trivial group has a non-trivial global point requires something stronger than plain ZF.

>> No.9677224

>>9677223
Explain ZF using your own words.

>> No.9677228

>>9677223
please state "the" definition of a group (and of a field while you're at it)

>> No.9677231

>>9677224
>Explain ZF using your own words.
Don't expect much, he/she can only troll.

>> No.9677238

>>9677231
I know his methods very well. I'm just trying to make him understand how nobody takes him seriously even if he copies and pastes some fancy words from Wikipedia to impress his online "friends". inah

>> No.9677252

>>9677224
How does one explain something formal like ZF in his own words? Read any standard description of it.
>>9677228
The correct definition of a group is a 1-object groupoid. Note that this definition doesn't imply the existence of non-trivial global points when viewing this group as a (possibly large) set.
The correct definition of a field may only be given using something stronger than ZF, so you need to specify which assumptions I'm allowed to use.

>> No.9677255

>>9677238
I just looked at his post history, quite sad indeed

>> No.9677258

>>9677252
What do you mean by "correct definition"?

>> No.9677260

>>9677252
A nice way to tell me you don't know what you are talking about, and won't even try to make it sound cool as it doesn't involve any categorical language.

>>9677255
Indeed it is. Sad posts from a sad boy.

>> No.9677262

>>9677255
I'm not registered on this website, so that's not really possible.
>>9677258
The definition which agrees with mathematical intuition as it currently stands.

>> No.9677268

>>9677260
>A nice way to tell me you don't know what you are talking about
How so? So far all I'm seeing is you being unable to tell me how exactly I'm wrong.
>categorical language
There is no non-trivial categorical language in my posts.

>> No.9677272

>>9677268
Of course there is no non-trivial categorical language in your posts, as that is where your understanding of category theory ends. Can you even prove easy stuff like Yoneda's lemma or Freyd's adjoint functor theorem? Or even that every monad is induced by an adjunction? If you can, please do it and explain your proof using your own words.

>> No.9677293

>>9677272
Do you need some help understanding the intuition behind these basics results? If so, what exactly are you having trouble with?
Or is it something else and you're just trying to make fun of me by wasting my time as you suggested in >>9677238? I've never seen a person so vehemently denying obvious stuff like this without ever giving any real arguments.

>> No.9677310

>>9677293
I am making fun of you. I have proved all of them myself ages ago, and am able to understand them very well (but I do admit I must reread the claim for Freyd's theorem at some point since I don't remember the exact conditions). You, on the other hand, have been a pet idiot for me to have fun with, but it seems you couldn't keep the show going any longer. I've had my fun for tonight, so I'll just go to bed and have my boyfriend cuddle me to sleep. You are free now, those are my last words to you as your online dominatrix.

>> No.9677326

>>9677310
I don't believe in the kind of elitism you're engaging in by thinking that people have to explain basic stuff everyone knows in order to "prove their worth". And why are you even trying to make fun of me? Is this some kind of coping mechanism against acknowledging how flawed your arguments are (even if subtly so)? That happens to all of us from time to time so there is no need to get upset over it. I just hope that you realize your mistakes even if you don't want to admit it publicly.

>> No.9677329

>>9677252
by your own definition groups are non-empty

>> No.9677335

>>9677329
They may be non-empty, but that isn't provable for arbitrary groups without extra assumptions. You can only show that they have a trivial point, which is a slightly weaker statement.

>> No.9677340
File: 171 KB, 538x338, TRINITY___DETRACTORS2.png [View same] [iqdb] [saucenao] [google]
9677340

>math

>> No.9677341

>>9677335
in your post >>9677209 you imply that empty groups exist, and you say that a group be pointed is a non-trivial assumption in ZF

both statements are false according to your own definitions, please think a bit more before you post something stupid next time

>> No.9677344

>>9677341
>you imply that empty groups exist
This is actually independent of ZF. And the statement "every group is pointed" is also independent. So you can't shown in plain ZF that empty groups exist or that every group has a non-trivial global point, although the existence of a trivial point follows trivially from the definition.

>> No.9677350

>>9677344
>accidentily defines groups as being non-empty and being pointed
but it's totally independent of ZF

I'd like to see you define fields as well so you can contradict yourself some more

>> No.9677359

>>9677350
A set being empty and having a trivial point is perfectly consistent with ZF. Fields work best when you assume AC, then the definition is the usual one you can find in any introductory text on algebra.

>> No.9677371

>>9677359
wrong

>> No.9677526

LADR is ok as a first exposure, right? From an initial glance I think I'd enjoy it more than Hoffman and Kunze, but will use both ultimately. I just don't want a fear of determinants to trip up my learning process and understanding, but my inexperienced self does tend to agree with the idea of introducing them later.

>> No.9677560

>>9677176
Delete this

>> No.9677571

>>9677526
Go for it if it appeals to you. I don't like it personally, but there are extraordinarily few math textbooks that are so bad they will actually hinder your learning. Mostly anything will do the job.

>> No.9677577

How do I prep for the Putnam? I've never done AIME/IMO and I am familiar with mathematics up until Calculus III.

>> No.9677582

How do I calculate an angular acceleration over time? Like if have an angular acceleration of 1 rad a second, how do I calculate how many times the object has rotated in a minute? I can only find formulas for a fixed angular velocity not constantly accelerating.

>> No.9677583

>>9677571
My stance prior to posting was the same (other than preferring LADR of course). But I’ve never before used a book that so vocally radically departs from standard pedagogical practices. Thanks for the input! Out of curiosity, why are you less fond of LADR? For awhile the cheesy title put me off, but after reading Down with Determinants I think I agree with the overall choice in topic progression (avoidance of determinants until the latter half).

>> No.9677586

>>9677577
Start with ‘The Art and Craft of Problem Solving’ by Zietz, and from there you’ll find your way. Here’s another reference:
http://math.mit.edu/%7Erstan/refs.pdf

>> No.9677588

>>9677586
>http://math.mit.edu/%7Erstan/refs.pdf
Thanks! Do you have any advice or tips/tricks about prepping or taking the exam (I presume you can speak from experience)?

>> No.9677598

>>9677582
Integrate acceleration twice to get the formula for the angular displacement. Plug in intitial values for angular velocity and displacement (zero I presume), and then you have angular displacement as a function of time. Divide by 2pi and that's the number of revolutions

>> No.9677601

>>9677598
i.e. theta(t) = 1/2 alpha t^2 + omega t + theta_0

and num_of_revolutions(t) = theta(t)/(2 * pi)

where alpha is acceleration, omega velocity, theta_0 initial displacement

>> No.9677602

>>9677577
By far the best thing you can do is attend live practice sessions if your university holds them. There's really no replacement for this.

Otherwise just spam problems, but do it intelligently. If you can't solve something study the solution until you buy into the idea that somebody could come up with it unaided, not just until you understand it.

I personally don't think textbooks are the best approach to study with because there's really no grand structure to competition problems, you just want to have a big-ass toolbox (seen lots of solutions) and be good at using it (done lots of problems).

>> No.9677605

>>9677598
>>9677601
Sweet, thanks anon

>> No.9677608

>>9677602
Thanks a lot. I'll be at MIT, which does hold such sessions, but I think I'll be overshadowed by the geniuses who finished multivariable in 6th grade and therefore not receive enough help from profs who I presume will focus on their golden eggs

>> No.9677617

>>9677583
I just don't think he actually provides any legitimate criticisms of determinants. All he does is claim they're "difficult" which is not a reason to not teach something, and "not taught well", in which case just teach them better.
It seems like a molehill of a problem being turned into a mountain so he can market his book.

>> No.9677667

>>9674311
I've never seen such useless math in my entire life.

>> No.9678063

>>9677577
I think you need at least a semester of real analysis and linear algebra, so I would look into that first

>> No.9678064

>>9670803
How can I use these symbols on 4chan?

>> No.9678118

>>9678064
check the sticky on "latex tutorial". There's a preview button in the corner of the reply box called "tex"

>> No.9678130
File: 974 KB, 960x738, ryys.png [View same] [iqdb] [saucenao] [google]
9678130

>>9677326
Blah blah blah. There were no mistakes on my behalf, and if there were I would simply have admitted them. This is an anonymous board. I have nothing to lose by saying I was wrong on something (assuming I was), but I wasn't so there is no reason for me to make such a ridiculous claim. Cry some more, and then get that job I told you to get.

>> No.9678155

GUYS WTF, MAPLE IS 2000 FUCKING DOLLARS

How the fuck can I, a student, pay for that? Why is it so expensive? Are there any free alternatives? Fuck, those people are crazy, are there people who pay 2000 dollars for that?

>> No.9678176

>>9678155
Just get a license through your uni mate, should be possible. Also, who the fuck uses maple anyway?

>> No.9678185

>>9678155
not sure if it works, but i found this if you want to try
https://mega.nz/#!hocl1Q4b!a_cEQ3rbtKxweYDoq0C2uE5Jk6V3A-17Z2SQpbYccQk

>> No.9678343

>>9678176
What do people use nowadays? I always thought maple was better than matlab and mathematica for mathematicians, are there better alternatives? I heard good things about Julia as well.

>> No.9678348

>>9678343
>I always thought maple was better than matlab and mathematica for mathematicians
This has never been said in the entire history of ever, unless you were looking at a paid review article there is no way someone could ever think that

>> No.9678370

>>9678343
>I always thought maple was better than matlab and mathematica for mathematicians

That's retarded. What are you looking to do with it anyway?

>> No.9678383

>>9678348
>This has never been said in the entire history of ever, unless you were looking at a paid review article there is no way someone could ever think that
>>9678370
>That's retarded. What are you looking to do with it anyway?
What do you two mean? There are many things Maple is better at than Mathematica and vice versa. Maple's excellent for number theory (especially cryptography)

>> No.9678542
File: 44 KB, 480x468, IMG_20171028_201836.jpg [View same] [iqdb] [saucenao] [google]
9678542

>>9677209
Listen, you moron. BY DEFINISHIUN 1 does not equal 0.

>> No.9678546

>>9678542
>Listen, you moron. BY DEFINISHIUN 1 does not equal 0.
It does in the trivial ring.

>> No.9678563

>>9677608
To be sure, they will prefer their 'golden eggs', but you can prove yourself through effort. Those kids have had the equivalent of MIT all of their lives. You didn't. Hence, it is not completely unreasonable for you to shoot up in the rankings after the first year, though don't expect too much for that year.

>> No.9678570

>>9678546
For a field's definition!!!!! You are so dull in the brain.

>> No.9678668

redpill me on [math] \mathbb{F}_1[/math]

>> No.9678863
File: 106 KB, 636x370, SENS_FOUNDATION_-_AUBREY_DE_GREY_(6838320854).jpg [View same] [iqdb] [saucenao] [google]
9678863

https://arxiv.org/abs/1804.02385
all of you fagots just got btfo by le pseudoscience antiaging man

>> No.9678947
File: 123 KB, 588x851, IMG_2344.jpg [View same] [iqdb] [saucenao] [google]
9678947

>>9670231
>A sphere in 3-space (also called a 2-sphere because it is a 2-dimensional object)
How is a sphere a 2 dimensional object? Not trolling, I'm just a brainlet.

>> No.9678958

>>9678947
Every point on the sphere has a neighbourhood homeomorphic to [math]\mathbb{R}^2[/math].

>> No.9678991
File: 123 KB, 300x290, sphericalcoord3.png [View same] [iqdb] [saucenao] [google]
9678991

>>9678947
Basically, you only need two coordinates to describe any point. Similarly a circle is 1-dimensional, every point is described by one number - it's angle. Because the size of the radius is fixed.


You can imagine a circle folding out to give a line, you can imagine a sphere folding out to give a surface (only kind of though, you need a point at infinity to really match them up).

Of course a ball (filled in sphere) is 3 dimensional because you also need to describe how far each point is from the origin, so 3 coordinates.

>> No.9679049

Can any bongs recommend me a GCSE-level mathematics textbook? An actual course, not like those CGP revision books. I've seen Greer recommended but the most recent edition was published in 92 and I'm worried that it's now irrelevant. Not that I want to actually sit the exams, mind.

>> No.9679590

>Riemannian GEOMETRY
>Textbooks rarely have pictures
>Stress formalism and rote symbol manipulation

>> No.9679591

I have a calculus and an algebra test next week (thursday, 26), if I start studying now, can I make it guys? My IQ is around 120 btw.

>> No.9679593
File: 1.38 MB, 3264x1836, IMAG0669.jpg [View same] [iqdb] [saucenao] [google]
9679593

Cauchy BTFO by based Abel

>> No.9679644

>>9678668
Delet this

>> No.9679660

>>9677178
Yes, now explain how Z/(2) can be immersed into Z/(3). Trivial my ass

>> No.9679678

>>9679593
saurce

>> No.9679862

Are there any current research programs comparable in scope to the Langlands program?

>> No.9679873

Newton's third law makes no fucking sense.
"For every action, there is an equal reaction" is fucking bullshit.
>Throw boulder in air
>Throw needle in air towards boulder
>They collide
>Both come to a total stop and drop straight to the ground, or bounce off each other.
Because according to the third law, the force that the needle exerts on the boulder should be equal to the force the boulder exerts on the needle. Which is pure fucking bullshit.
Prove me wrong.

>> No.9679881

>>9678668
It's a F_un field I know that much :^)

>> No.9679883

>>9679873
>Newton's third law
Refer to >>>/toy/ or >>>/sci/sqt/ for physics discussion.

>> No.9679886

>>9679873
Not math desu, take this shit out of here. Anyway I can't tell if you're trolling or seriously misunderstanding. The needle will bounce of the boulder, and in doing so force the boulder in the opposite direction. But because the needle is fucking tiny the boulder will barely move, probably not even perceptibly.

I barely know any physics by the way.

>> No.9679959
File: 25 KB, 620x348, bumimplants.jpg [View same] [iqdb] [saucenao] [google]
9679959

Posting here because it really doesnt warrant its own thread.

How much of a profit does advantage poker playing actually make and over what peroid of time do you have to do it to make a real profit?

>> No.9679968

>>9679959
Ask in the appropriate thread for stupid questions >>>/sci/sqt/.

>> No.9680076

>>9679873
The force IS the same, but force accelerates objects proportional to their mass. I agree that the term "action" is vague and confusing though. Reading the way people used to describe physical equations makes me really grateful for modern rigor.

>> No.9680106

>>9680076
see >>9679883

>> No.9680424

going to quit life and study math out in the woods of Idaho, anybody want to join. Maybe make a convent like that book Anathem

>> No.9680510

>>9680424
what are you going to eat?

>> No.9680514
File: 7 KB, 237x213, kops.jpg [View same] [iqdb] [saucenao] [google]
9680514

I checked on my elementary high school math skills and I can't wrap my head around it. For an example:

17-2p=2p+5+2p

Combine like terms

17-2p = 4p + 5

Subtract -4

17 - 6p = 5

Subtract 17

-6p = -12

Divide by -6

p= -2

But when you are trying to get rid of the numbers, how do you know you have to subtract -4 to get rid of the 2p + 2p on the right side, and not get rid of the -2p on the left side?

Like:

17-2p=2p+5+2p

Add +2p and also subtract -5 to get rid of the 5 on the right side

12 = 4p + 4p

12 = 8p

8p = 12

12/8 = 1.5

p = 1.5

Is the only way to know this is wrong to manually enter it into the equation to check it, I thought there is a logic you can follow to do it right the first time.

>> No.9680526

>>9680514
in your first "solution", -12/-6 = 2, not -2
in your second, you added an extra 2p to the right side:
17-2p = 2p + 5 + 2p = 5 + 4p
17 - 2p - 5 = 5 + 4p - 5
12 - 2p = 4p
12 - 2p + 2 p = 4p + 2p
12 = 6p
12/6= 6p/6
2 = p

Don't do more than one step at a time until you are more comfortable with these manipulations, it seems like you don't quite know what you're doing. The fundamental idea is you do the same thing to each side (provided it doesn't give you extra solutions)

>> No.9680527

>>9679590
>algebraic geometry
>it's just a commutative algebra textbook

>> No.9680538

Does anyone have the meme textbook quote that says "proof: Think"

>> No.9680547

>>9680514
17-2p=2p+5+2p
17-2p=4p+5
17=6p+5
12=6p
2=p

>> No.9680573

>>9679593
What book is this?

>> No.9680633

>>9671882
Well as usual, it depends on what you call reasonable standards. For a beginner, many arguments can seem handwavy (just take this and glue it over there blabla), but it is usually made rigorous in writing

>> No.9680637

>>9670231
1 - 1 - 1= - 1

>> No.9680691

>>9679862
mochizuki's program

>> No.9680694
File: 366 KB, 890x343, 1512127431286.png [View same] [iqdb] [saucenao] [google]
9680694

>>9680538

>> No.9680752

>>9680424
My unironic goal in life is to form a commune where people can study math and philosophy and literature. We'll have a comfy house with a big library and vegetables gardens and shit. It'll be great.

>> No.9680874

>>9680694
Cheers la

>> No.9681785
File: 39 KB, 550x261, Untitled.png [View same] [iqdb] [saucenao] [google]
9681785

i posted this in /sqt/, but didnt really get much of a response and i figure there are lots of people who know algebra things here

can someone explain what im misunderstanding about what's in the box:
i dont understand why [math] \deg g(X),\deg h(X)>0 [/math] should follow from [math] f(X) [/math] being reducible in [math] \mathbb{Z}[X] [/math].
for example, suppose [math] f(X)=4 [/math]. then [math] f(X) [/math] is reducible in [math] \mathbb{Z}[X] [/math] since 4 is not a unit, but [math] \deg 4=0 [/math]

one anon in /sqt/ thought maybe the lemma should also assume deg f>0, but idk.
i've put the definition of irreducible in the picture as someone mentioned it last time

>> No.9681809

>>9681785
That's not how I've typically seen reducibility defined, it's generally done in such a way that constant polynomials don't count as factors. Honestly I think it's a mistake, as I can't imagine they mean for you to treat f(x) = 4 as reducible in Z[x].

>> No.9681815

>>9681809
I should clarify I'm talking about reducible _polynomials_, f(x) = 4 is certainly a reducible _element_ in the sense that factors into non-units.

>> No.9681897

>>9681809
>>9681785
as i mentioned in sqt, im pretty sure the lemma should also require deg f >0

>> No.9681913

>>9681897
It follows from primitivity. If it was of degree 0, then it would need to be such that no non-invertible integer divides its constant term, and thus it would have to be 1 or -1. Now, the only polynomials we could then have it be the product of would be either both 1, or 1 and -1. Since both of these are units in the ring, you can't have it be of degree 0.

>> No.9681967
File: 29 KB, 331x500, c1f558e20f907e1b8c4b31b3e1d52c83-d.jpg [View same] [iqdb] [saucenao] [google]
9681967

B^)

>> No.9682234

>>9681785
deg g(x), deg h(x)>0 is just the assumption that f(x) is primitive

>> No.9682339

http://www.math.wayne.edu/~isaksen/Expository/carrying.pdf

>A Cohomological Viewpoint on Elementary School Arithmetic

>> No.9682370

>>9680510
there will be a farm where one goes to symbolically toil away at a proof while physically toiling away at manual labor

>> No.9682792
File: 445 KB, 1000x640, g1_r28_a1f-1.gif [View same] [iqdb] [saucenao] [google]
9682792

https://icerm.brown.edu/simonscollaboration/
>Our common perspective is that advances in computational techniques accelerate research in arithmetic geometry and number theory, both as a source of data and examples, and as an impetus for effective results. The dynamic interplay between experiment, theory, and computation has historically played a pivotal role in the development of number theory. In the 18th and 19th centuries Euler and Gauss undertook extensive calculations by hand in the pursuit of data to help formulate and refine conjectures, and as a source of counter examples. In the 20th century systematic computations of elliptic curves and their L-functions led to the formulation of the Sato-Tate and modularity conjectures, both of which have now been proved, and the conjecture of Birch and Swinnerton-Dyer, which remains open but has been proved in some special cases.

>In the 21st century the frontier of research in arithmetic geometry has moved on to curves of higher genus, abelian varieties, and K3 surfaces. Although available computational resources have grown dramatically. the development and implementation of practical algorithms has lagged behind the theory; we seek to correct this imbalance. In contrast to the situation with elliptic curves, in higher dimensions brute force computation yields very little. To obtain practical algorithms one must exploit the theoretical infrastructure of modern arithmetic geometry.

>> No.9682939

What's the relation between homology and locally constant functions?

>> No.9682941
File: 58 KB, 540x960, 1524095284536.jpg [View same] [iqdb] [saucenao] [google]
9682941

Who is in the right here?

>> No.9682982

>>9682941
Who gives a fuck? Go ask your elementary school teacher instead.

>> No.9683035
File: 39 KB, 524x486, 1524032066982.jpg [View same] [iqdb] [saucenao] [google]
9683035

>>9682941
(you), for attempting to start shit over the operator precedence of * and + like the uninteresting freshman you are

>> No.9683038

>>9674297
every time

>> No.9683098

>>9670271
>>9670276
我不知道这个模因,家人。

>> No.9683162

>>9682939
Local systems in algebraic topology, which define twisted cohomology theories, are equivalent to Locally constant sheaves.

The twisted cohomology given by a local system, is the same as the sheaf cohomology w.r.t. the corresponding locally constant sheaf.

Also note in nice cases, local systems are the same as vector bundles with flat connection. And the twisted cohomology is the twisted deRham cohomology defined by the the exterior covariant derivative.

>> No.9683188

>>9680752
You mean a university?

>> No.9683213

>>9670231
Great thread OP:

>> No.9683422
File: 3.05 MB, 600x600, TauBoo_nrad26.gif [View same] [iqdb] [saucenao] [google]
9683422

hey math fags, I'm quitting mechanical engineering for computer science and math.

I have the option to to a pure computer science bachelor or computer science and math bachelor (50/50)

I heard people say the more knowledge in math you have, the more advantaged you are to other people. I want to go to grad school eventually so I need gud grades. Which one should I choose if I'm 'meh' at math?

btw in the computer science bachelor I do calc 1 2 and 3, linear algebra and discret math

>> No.9683432

>>9683422
Wrong thread. Ask in >>>/sci/sqt/ or >>>/adv/.

>> No.9683440

How does [eqn]\sum_{m=1}^\infty \sum_{j=1}^\infty j^{2k-1}q^{ mj}[/eqn] become [eqn]\sum_{n=1}^\infty \sigma_{2k-1}(n) q^{n}[/eqn] where [math]\sigma _{2k-1}(n)=\sum _{0<d|n} d^{sk-1}[/math] and [math]q=e^{2\pi i x}[/math]. My book says by setting [math]mj=n[/math] and that's it..

>> No.9683445

>>9683432
alright. Would be cool if we had a /sci/adv

I'll still lurk here, love this general.

>> No.9683448

>>9683440
also [math]x[/math] is in the upper half complex plane and the definition of sigma should have a 2 in the sum, not an s

>> No.9683471

>>9683440
never mind, got it

>> No.9683473

>>9683471
Idiot

>> No.9683586

I visited my granny today again. We discussed topology, Strasserism and how the gas attack in Syria was fake. She understood quite nicely when I explained her how homotopy equivalence works.

>> No.9683596

>>9683586
>the gas attack in Syria was fake
https://www.reuters.com/article/us-mideast-crisis-syria-france-intellige/french-declassified-intelligence-report-on-syria-gas-attacks-idUSKBN1HL0N1

>> No.9683600

>>9683596
Sure, believe that shit. France was one of the countries attacking Syria, so of course their opinion is that Assad was behind it.

>> No.9683619

>>9683596

It was fake as shit, the "white helmets" were involved and they've faked this stuff before: https://youtu.be/3HCFol7g-FU

>> No.9684406

>>9683596
>>9683600
>>9683619
>>>/pol/168756660

>> No.9684409

>>9684406
>>>>>>/pol/168756660
You have to go back.

>> No.9684419
File: 421 KB, 849x1199, 1521411785355.png [View same] [iqdb] [saucenao] [google]
9684419

Set Theory is a fucking fraud guys. Are there better mathematical foundations?

>> No.9684422

>>9684419
>Set Theory is a fucking fraud guys.
What do you mean?

>> No.9684425

>>9684422
my professor told me some shit i didnt want to hear, he pulled the bandaid off really quick

my parents are mathemeticians and they hate that i now question set theory, they hate that they pay 50 G's a year so the professor can BLOW MY BIND

>> No.9684436

>>9684425
>my professor told me some shit i didnt want to hear
What did he say?

>> No.9684502

>>9684419
It is based on hope, hope that a model satisfying the axioms exists.

>> No.9684868

>>9684419
yes, type theory

>> No.9684874

trying to get my head around how a traced category works.. I've read the definiton a hundred times but I still can't get any intuition. anyone have some pointers?

>> No.9684914

>>9680752
Sign me up, that sounds amazing. I have some p cool math books to contribute.

>> No.9685230

redpill me on stacks

>> No.9685443

>>9684419
>mathematical foundations
Ask the guys over at >>>/lit/.

>> No.9685585
File: 1.02 MB, 2080x2386, pls no bulli.png [View same] [iqdb] [saucenao] [google]
9685585

>>9680752
>a commune where people can study math and philosophy and literature
Hey, I was thinking about this as well (although in my mind I had fashioned it after a monastery; a mathematicians' monastic order). Where are you from?

>> No.9685595

>>9684419
Shimarin a qt.

>> No.9685687

>>9685585
Finn whore kys

>> No.9685712

>>9685687
I am not he.

>> No.9685713

>>9685712
him*

>> No.9685717

>>9670231
1+1=2 prove me wrong

>> No.9685916
File: 79 KB, 781x1000, 1410128850486.png [View same] [iqdb] [saucenao] [google]
9685916

>>9670231
Hey, I was just reading about him the other day. From an absolute brainlet point of view, I don't fully understand the controversy around his IUT. To me, the drama seems to be, (apart from being top-tier, advanced mathematics) that "OMG he used/ introduced new mathematics to solve an existing problem." With mathematics being an infinite science and all, how is that not expected? Weren't integrals and everything else new at once? Anyways, I digress.

To further my point of being a brainlet, I have a brief feels story. Math major btw. Last semester I had the task of finishing a bunch of nasty humanities and stuff (including foreign language requirements) all within one semester due to a certain deadline. I had no time for math, unfortunately. This semester I got stuck in an 'intro Complex Analysis'-esque class despite my wariness over my math being a bit rusty from the previous semester. I've done horribly. My question is, as somebody who plans on solely focusing on discrete math in my career, how f**ked am I? I don't know if my complex knowledge will ever recover, and I am worried if it might hinder me in future studies of discrete math (including topics like and related to combinatorics, number theory, crypto). I get the basics (arithmetic, simple calculus with complex numbers, elementary functions), if that matters. Will I need much complex analysis knowledge for a future in discrete math?

>> No.9685927

>>9685916
>mathematics being an infinite science
Mathematics is not a science.

>> No.9685931

>>9685916
>I don't fully understand the controversy around his IUT.
The main "controversy" now seems to be the proof of Corollary 3.12 in http://www.kurims.kyoto-u.ac.jp/~motizuki/Inter-universal%20Teichmuller%20Theory%20III.pdf

See
http://www.math.columbia.edu/~woit/wordpress/?p=9871
https://galoisrepresentations.wordpress.com/2017/12/17/the-abc-conjecture-has-still-not-been-proved/

>> No.9686066

>>9685916
let [math]\mathbb{F}[/math] have characteristic 2. Then [math]1+1=0[/math]. [math]\mathbb{QED}[/math]

>> No.9686068

>>9686066
>>9685717
meant for xir

>> No.9686072

>>9685916
>discrete math
No such thing. Try asking in the engineering threads.

>> No.9686076
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9686076

>No such thing. Try asking the engineering threads.

>> No.9686081

>>9685916
>discrete math
>topics like and related to combinatorics, number theory, crypto
>arithmetic, simple calculus with complex numbers, elementary functions
Wrong thread. This is /mg/, not "engineering general".

>> No.9686082

9686072
9686081
same fag

>> No.9686265

>>9676572
My library has a bin for free books. Just grab whenever you want. Wish I had some to donate though

>> No.9686348

If we're given a square matrix A that is near triangular (e.g. less than 3 steps away by row reduction to become a triangular matrix), can you use the triangular matrix A' to calculate a characteristic poly?

>> No.9686492

>>9686348
No.

>> No.9686534

>>9686492
There's a bunch of proofs by example but how do I prove it's not the case? I'm stuck at [math]det(A-\lambda I)/neq det(/Pi^n_{i=1}E_iA-\lambda I)[/math]. Where product represents the elementary matrices corresponding to the row operations to get A'.l

>> No.9686549

>>9686534
Not him, but what even is your question?

>can you use the triangular matrix A' to calculate a characteristic poly?
How could you possibly prove this?

>> No.9686559

>>9686549
>Can you use the triangular matrix A' to calculate a characteristic polynomial for A
Forgot to add that last bit there in the OP.
But I was curious because I saw a lot of cases like this until a few hours ago. Honestly, I just wanted a faster way to compute a characteristic polynomial for a big matrix by hand that was a row switch and a row addition away from being diagonal.

>> No.9686593

>>9686559
>Forgot to add that last bit there in the OP.
I didn't have a Problem understanding that.
But this isn't a mathematical question, of course there *might* be a way to use this, but how could you possibly prove it otherwise.

Have you tried always developing in the first row, at least in the case that the additional entries are to be found in the lower sub diagonal it should speed up the process.

But I really do not see how you would go about proving the nonexistence of a method.

>by hand
What the fuck.

>> No.9686680

>>9686559
Every matrix has a characteristic polynomial. Being triangular ain't got nothing to do with that.

>> No.9686838

>>9686680
I know that much. But it would be easier to get the characteristic polynomial of A if it were triangular. Since you're going to get zeros above or below anyways it's just going to be a product of entries along the diagonal.

>>9686593
I have. For matrices that have rows of just one nonzero entry for each row that not diagonal is easy. In most cases it turns out to be 0 since some of the columns turn out to be linearly dependent. After reading the response though I see why this is a pretty bad question.
>By hand
Yeah. It was on a practice exam and no calculators allowed. So I was banking on some trick to help reduce it to something simpler.

>> No.9686843

>>9686838
>in most it turns out to be zero since some of the columns turned out to be linearly dependent
Meant to omit that part. Product of bad notes

>> No.9686929

How do I prove that [math]e^{x^{2}}[/math] has no elementary function representation for an anti-derivative?

>> No.9686961
File: 468 KB, 722x927, qt hand rubbing intensifies.png [View same] [iqdb] [saucenao] [google]
9686961

I have a confession to make. I am an ashkenazi jew.

>>9686929
Google it ffs.

>> No.9686972

>>9686961
rude.

>> No.9686983

>>9686972
I'm getting really tired with people asking shit they can easily find answers for after literally 15 seconds on google.

>> No.9686993

>>9686983
It's to stimulate conversation in the deadest (and frankly lowest quality) general on /sci/. You should be grateful.

>> No.9687041

>>9687040
new
>>9687040

>> No.9687043

>>9686993
Good luck with that.

>> No.9687059

>>9686993
Which general is less dead than /mg/?

>> No.9687068

>>9685916
While complex analysis may not be that useful in ordinary discrete math, it is pretty important in number theory, but possibly not the number theory related to cryptography. There's actually a bridge between subjects like combinatorics and analysis but I doubt they're the ones you're interested in (since you mentioned crypto). Something that is pretty interesting is the use of differential/algebraic geometry for computational purposes. But no, sucking at complex analysis shouldn't fuck you over when it comes to most discrete math.

>> No.9687145

>>9687068
Thanks anon. You reinforced a lot of what I hoped for/ believed to be true.

I figured it was pertinent to number theory. My professor for this cursed complex class was some sort of number theory whiz back in his time and this complex stuff is like a second language to him. So, I expected as much.

That being said, I'd love to understand it more at some later point in time. Just was hoping this murky spot in my education doesn't completely doom me.

>> No.9687958

>>9687059
sqt, ironically more mentally stimulating too