[ 3 / biz / cgl / ck / diy / fa / ic / jp / lit / sci / vr / vt ] [ index / top / reports ] [ become a patron ] [ status ]
2023-11: Warosu is now out of extended maintenance.

/sci/ - Science & Math


View post   

File: 163 KB, 1920x1080, WIN_20201205_03_52_39_Pro.jpg [View same] [iqdb] [saucenao] [google]
12424218 No.12424218 [Reply] [Original]

Math, generally
>demiurge edition
Talk maths

Alte: >>12410456

>> No.12424233

>>12424218
HOLY SHIT I HATE GERMANS SO MUCH

>> No.12424243
File: 60 KB, 764x382, LinealRadial.jpg [View same] [iqdb] [saucenao] [google]
12424243

Alternate OP image for the less artistically inclined

>> No.12424262

How do I into geometry and stats?
I only know calc, lin a, and Diffies from college.
also I want into graph theory.

>> No.12424271

>>12424262
>stats
Buy a book
>geometry
Just look at shapes

>> No.12424276

>the stock market Chads are in my department again for their symposium

'ate em simple as

>> No.12424314

For a linear differential equation of order n, we know that there are n solutions. Is there a connection between this and the fundamental theorem of algebra and if so is there a good paper on it? It's trivially easy to see for equations with constant coefficients but I'm curious about the other cases.

>> No.12424323

>>12424271
any meme picture guides?

>> No.12424339

>>12424276
How's life as an indentured servant treating you?

>> No.12424355

>>12424314
Look for connections between gaussian elimination and theory of algebra, is my guess

>>12424323
If you need memes to tell you what to do youre NGMI.

>> No.12424368

>>12424355
>Look for connections between gaussian elimination and theory of algebra, is my guess
Is it an unanswered question?

>> No.12424373

>>12424355
>If you need memes to tell you what to do youre NGMI.
don't care.

>> No.12424376

>>12424368
I don't know, I haven't looked into it, Im just replying to inspire you to find a solution yourself. But when you say "the connection", that can be diverse, there are infinite relations between infinite sets. So in a sense it can never be answered, at least not fully.

>> No.12424382

>>12424373
Not saying that you're not gonna make it, bro. Just saying that your attitude needs to be changed. Look for books yourself rather than blindly following the advice of some halfway braindead anime trannies on 4chan.

>> No.12424384

>>12424243
>for the less artistically inclined
AKA unimaginative code monkey drones

>> No.12424405

>>12424382
going to google and typing "how to learn statistics" one results in meme articles and websites wanting my email
searching "how to learn geometry" brings up high school tier retardation.

>> No.12424429

>>12424405
1. Go to any half-way respected university math department website.
2. Read the course outline for math majors.
3. Go to course webpages and find book titles.
4. Obtain books from interweb.
5. ????
6. Profit.

>> No.12424433

Sorry if I'm being a cunt, since I've already posted a thread, but does anyone have any additions or critiques on this undergrad reading list? So far I've got
Basic Algebra I and II - Jacobson
Baby, Papa and Grandpa Rudin
Introduction to Topology - Borisovich et al.
A Concise Course in Algebraic Topology - May
Introduction to Smooth Manifolds - Lee
Partial Differential Equations - Evans
A Course in Arithmetic - Serre
Geometry, Topology and Physics - Nakahara

>> No.12424442

>>12424218

> my university has "woman in mathematics" meetings for undergrads
> last year I went to one
> no undergrad girls showed up
> me and 4 other undergrad boys showed up
> grad student ladies were really hot
> it was kinda funny

>> No.12424451

>>12424433
Can't go wrong with Munkres for point-set topology.

>> No.12424460

>>12424442
We always get tons of undergrad women at ours. No guys ever come (they're not allowed) but the undergrads all want to be pampered data science meme professionals and think I'm a nerd for actually liking math. :/

>> No.12424482

>>12424451
Is there much point in adding it in with what I already have though? I like Borisovich for topology, because he is fairly concise, while still giving some nice exposition, whereas Munkres seems like a much longer and more tedious slog. Would I be missing out on much point-set topology by foregoing Munkres?

>> No.12424492

>>12424433
>A Concise Course in Algebraic Topology - May
no, it's far too advanced for a first reading in algebraic topology

>> No.12424500

>>12424492
First reading would be in Borisovich, no? He goes over homotopy and homology, and introduces category theory.

>> No.12424533

>>12424262
>also I want into graph theory.
Here's a good book which will help you get into one of those fancy european universities who learn how to solve the Riemann hypothesis on the first day of orientation week -> https://www.amazon.ca/lagrapheur-intrigues-policières-saveur-mathématique/dp/B006W9Q1Y2/ref=tmm_pap_swatch_0?_encoding=UTF8&qid=&sr=

or if you're boring, this one looks pretty nice (especially for the price) https://www.amazon.com/Introduction-Graph-Theory-Richard-Trudeau/dp/0486678709/ref=sr_1_1?dchild=1&keywords=graph+theory&qid=1607211188&sr=8-1

>> No.12424653

>>12424482
I can't compare because I've never heard of the book you're thinking of using. My department uses it as the standard text for undergrad topology and I found it quite thorough and enjoyable. It's a tome though, not meant to be read cover to cover when first seeing topology.

>> No.12424719

>>12424653
How would you read Munkres then? Currently I'm working through it from the beginning, not skipping anything but maybe skimming some obvious proofs

>> No.12424746

>>12424719
Well I didn't originally read it by itself since I was in a class, but I'd say up to section 37 on the Tychonoff Theorem, skipping starred sections, is basically a solid undergraduate course.

>> No.12425020

i'm reading Euclid's Elements for a class, and i don't quite understand what is meant in Book X Proposition 10 "the ratio which a square number has to a square number." what does this mean?

also i apologize to the anon who said that it is important to pick a good translation for Elements, when i doubted him/her/they by saying "isn't Elements just a bunch of lines on a paper." it becomes a lot more complicated than that....

>> No.12425161

Does anyone know where I can find an english translation of Galois' original papers?

>>12425020
My assumption is he just means the ratio A/B where A and B are both equal to some integer . So 36 25 49 100 all work, but 17 and 12 don't

>> No.12425175

>>12425161
*Some integer squared

>> No.12425184

>>12424460
Dinask tranny

>> No.12425249

>>12425161
yeah i thought so too, but then what is the relation between them?

also, the link doesn't quite work but hopefully its better than nothing

http://www.galois-group.net/g/EN/intro.html

>> No.12425292

>>12424442
uoft?

>> No.12425309

Is Gorodontsev's Algebra book a good intro?

>> No.12425342

>>12425249
>Set out two numbers B and C which do not have to one another the ratio which a square number has to a square number, that is, which are not similar plane numbers
So the ratio of lengths between B and C can't be anything of the form B/C = Q/Z where Q and Z are squares of some int. So B/C can be 2/11, but not 36/64

Ty for the link

>> No.12425429
File: 72 KB, 1452x344, 1588642526759.png [View same] [iqdb] [saucenao] [google]
12425429

I found this.

>> No.12425442
File: 114 KB, 1764x567, 1585136902319.png [View same] [iqdb] [saucenao] [google]
12425442

>>12425429
What the fuck is with adding integers and minus 1/12?

>> No.12425641
File: 80 KB, 1150x826, AOC1150x826.jpg [View same] [iqdb] [saucenao] [google]
12425641

Wtf does she has to do with the axiom of choice?

>> No.12425650

>>12425641
She's a politician trying to change the age of consent, nothing to do with set theory.

>> No.12426074
File: 1.50 MB, 1440x3040, Screenshot_20201206-042941_QuickPic.jpg [View same] [iqdb] [saucenao] [google]
12426074

I know the answer but I still don't understand how you solve it

>> No.12426085

have you guys learned rational trigonometry yet?
https://www.youtube.com/playlist?list=PL3C58498718451C47

>> No.12426177
File: 374 KB, 444x720, kgr1V0B.png [View same] [iqdb] [saucenao] [google]
12426177

>>12426085
>studying a contrived variant of planar geo/trigonometry tailored to satisfy one person's whims
i'm pretty sure everyone has better things to do

>> No.12426201

>>12426177
>anime posting
opinion discarded

>> No.12426268

>>12424433
This reads more like a list of books to refresh your knowledge with rather than learn for the first time. No one should be learning out of Serre in undergrad.

>> No.12426274

>>12426201
this

>> No.12426447

>>12425429
>>12425442
Since the function is mirrored between -1 and 0 at x=-0.5, you'd always get a sum of -1, no matter what y-value in the value range you plug in there.

>> No.12426464

>>12425442
I see, so [math]\sum_{n=1}^{-0.2} n = \frac{-1}{12}[/math]

>> No.12426574

ok guys let's settle this once and for all
[math]\phi[/math] or [math]\varphi[/math]?

>> No.12426583

>>12426574

both

>> No.12426628

>>12424218
n/2
3n+1

n/2 for 1/3 domain space of n
(every other even)
3n+1 for 2/3 domain space of n
(Odd and every other even)

Inversely related wrt n
(n/2)(2/3n)=1/3
(3n)(1/3n)+1(1/3n)=
1+1/3n=
1+lim(1/3n)=
1

Functions converge to 1

>> No.12426678

i need a source, not a book, but a good sum up of a field in math. the field is practically just proving limits and other qualities of groups and sets. any clue anyone?

>> No.12426713

got my algebra exam tomorrow bros, never been so unprepared ;-;

>> No.12426827

>>12426713
its ok i just got 5 out of 100 in a classical physics midterm

>> No.12426849

Why are Russian math books so good bros

>> No.12426987

>>12426268
I prefer learning from books like that though. I get bored if the book holds your hand, or if I'm not struggling to understand the concepts.

>> No.12427022

>>12426574
[math]\phi[/math] because it's faster to write.
My choices go [math]\phi \ \psi \ \varphi[/math] and then random available greek letters.

>> No.12427141

>>12426849
Which ones so you particularly like

>> No.12427194

How can I prove a real function can't have infinite derivative on the whole of a nontrivial interval?
(reason I'm not asking on /sqt/ is I've had bad luck there with Qs like this)

>> No.12427315

>>12426849
years of the Soviet Union actually investing in education and I&D while the West just jerked off over the market or some shit

>> No.12427804

>>12426074

I have no idea what I’m talking about, but:

you have 101 elements, so the maximum checks is log(101)/log(2), which rounds up to 7

>> No.12427810
File: 324 KB, 600x588, 39525513_p0.jpg [View same] [iqdb] [saucenao] [google]
12427810

They say love is a choice. Does the axiom of choice have anything to say on this subject? Checkmate atheists. (I have come to the conclusion that math is a waste of time. Disregard learning, acquire pussy.)

>> No.12427836

>>12426177
based. fuck finitists

>> No.12427955
File: 11 KB, 417x377, kanashii kaeru.png [View same] [iqdb] [saucenao] [google]
12427955

>>12427810
sir you made me sad

>>12427194
can you make your question more precise
what's infinite derivative

>> No.12428007

>>12427955
I make myself sad too. I was sexually abused by my babysitter when I was 6. Does that mean I am no longer a virgin?

>> No.12428046

>>12427955
>can you make your question more precise
>what's infinite derivative
Meant simply f'(x) = inf for every x in the interval. As in sgn(0) = inf

>> No.12428110

>>12427810
What if I'm gay, but genuinly not interested in acquiring the male equivalent?
If I don't kms, what I do is irrelevant, I better invest the time in something interesting. My life will be impotent anyway.

>> No.12428124

>>12428110
Are you interested in being a househusband?

>> No.12428143

>>12428124
I'm not aware of that word. (ESL)

>> No.12428144

>>12427194
>>12427955
>>12428046
I guess you're asking why can't a function satisfy
[eqn]\lim_{h\to x}\left| \frac{f(x+h)-f(x)}{h} \right| = \infty[/eqn]
on some interval

>> No.12428151

>>12428144
h->0 obviously

>> No.12428178

>>12428144
>>12428151
It's not exactly equivalent as I had in mind a constant signed infinity, but still would be interested in such function or a proof it doesn't exist.

>> No.12428209

>>12428178
right, just delete the absolute value then
do you know for sure that the statement is true?

>> No.12428234

>>12428209
>do you know for sure that the statement is true?
It might very well be untrue..

>> No.12428255
File: 69 KB, 576x707, 100558394_1426786527509443_5005568097524908032_n.jpg [View same] [iqdb] [saucenao] [google]
12428255

you should be able to solve this

>> No.12428262

>>12424218
I assume someone here has taken a course in complex analysis. am I missing out by not taking this? I can only fit so many classes into my schedule.

>> No.12428263

>>12428255
>>>/g/

>> No.12428308
File: 579 KB, 800x1046, c.png [View same] [iqdb] [saucenao] [google]
12428308

>>12428144
>>12428209
solution for the statement without abs value:
assume the condition is true for a function f on an interval [a, b], choose some n
then for each x in the interval, you can pick [math]l_x < x < r_x[/math] such that [math]\frac{f(p) - f(x)}{p - x} > n[/math] for all [math]p \in (l_x, r_x)\setminus \{ x \}[/math]
so this implies [math]\frac{f(p) - f(q)}{p - q} > n[/math] for all [math]p, q \in (l_x, r_x)\setminus \{ x \}[/math]
now by compactness choose a finite covering of [a, b] by the intervals [math](l_x, r_x)[/math] and fuck around to get [math]f(b) - f(a) \geq n(b-a)[/math]
but obviously that can't be true for all n, so there's a contradiction

>> No.12428361

>>12428308
I'm not 100% convinced, but seems legit. Thanks

>> No.12428368

>>12428124
I'm curious, why did you ask?

>> No.12428386

>>12428308
So for the courageous we've still got the absolute value version. This is a nice and simple proof, but the impossibility must follow from uncountability, I believe. Simply can't act discretely with it.

>> No.12428564

>>12428143
It means you stay at my house and do all the chores and provide definitely not gay comfort for me when I get back from work.

>> No.12428566

>>12428368
Probably because I’m interested in having a househusband?

>> No.12428573

>>12428262
It is something you will definitely see in grad school again if you plan to go down that route. What would you rather take instead?

>> No.12428639

Brainlet moment here. If [math](f^{-1})'(x) = \frac{1}{f'(x)}[/math], when [math]f'(x) \neq 0[/math], why isn't [math]log'(x)=\frac{1}{exp~x}[/math] (on positive reals obviously)?

>> No.12428644

>>12428639
>If (f−1)(x)=1f(x)(f−1)(x)=1f(x)
this is not true. think about it.

>> No.12428649

>>12428644
Brainlet moment cured, thanks.
It's just that for f(a)=b, the inverse derives to 1/f'(a) at b.

>> No.12428700

>>12428573
combinatorics and graph theory.

>> No.12428765

>>12424233
ok chang

>> No.12428864

What is the use behind Euler's theorem on homogenous functions? I've had the proof as an exercise but even after googling I have no idea what's the point.

>> No.12428937

What's a good book on analytical geometry for someone who pursues a math major?

>> No.12428973

>>12428700
If you are willing to learn complex analysis on your own during your winter or summer break, then it is not as essential as a solid foundation in analysis, algebra, and topology, but it is good to have.

>> No.12428977
File: 14 KB, 300x180, _406958_li300.jpg [View same] [iqdb] [saucenao] [google]
12428977

You ever be like "wait i'm not in high school anymore"

>>12428937
>analytical geometry
any trig book probably

>> No.12429161 [DELETED] 
File: 151 KB, 817x1000, Frans_Hals_-_Portret_van_René_Descartes.jpg [View same] [iqdb] [saucenao] [google]
12429161

hello Senpai
who wan self-learn ? join our autists
we have all manner of degenerates, including but not limited to
rust programmers, category theorists, one (1) communists, and of course a tranner
wide ranging interests Guaranteed to Enrich and Officially Debunk ur worldview
we're doing Advent of Code 2020, join for the wild ride
previous projects include SICP, overcoming dekinai, forallx, GEB groupread, attempt x to kill slack, and some dude doing combinatorics really loudly

Unironically, we're a group of people interested in all kinds of intellectual subjects related to STEM and the humanities. Looking for more maff people.
https://desu-cartes.org/signup.html
dog bless

>> No.12429256

>>12429161
>dekinai
what is this

>> No.12429594
File: 54 KB, 735x500, comic2-3599.png [View same] [iqdb] [saucenao] [google]
12429594

Post trivia about 18

>> No.12429616

>>12429594
18 is the smallest difference between an emirp and its reverse

>> No.12429871

>>12429594
17 = 17 * 0.99...

>> No.12429914
File: 48 KB, 250x250, 1583109117933.png [View same] [iqdb] [saucenao] [google]
12429914

>First time doing Analysis
>Professor gives a 5 exercise list about the first chapter of the book
>Can't solve a single one of those questions
>Several people in class managed to solve them all
Sighs, I'm so tired of this. I'm starting to believe I chose the wrong field. I love mathematics, but I can't solve basic analysis shit, I'm completely worthless, this is so sad, if I fail this semester I'll quit maths even if it will pain me very much.

>> No.12429917

>>12429914
Is that baby rudin?

>> No.12429919

>>12429914
me too bro, got an analysis exam later today

can someone help me please, im trying to solve a singular perturbation problem but I'm having trouble rescaling

i have Ex^3 + x -1 = 0, where E is epsilon

what should i rescale x = y/(E^v) as?

>> No.12429920

>>12429914
is this your first proof-based course?

>> No.12429923

>>12429917
Yeah.
>>12429920
It is, I read a little of How to Prove It at the beginning of the year to get ready for proof based courses, but I already forgot most things of the book and the ones I remember didn't help me much.

>> No.12429945

>>12429923
transition from computational math to pure math is insanely hard. the people from your class who completed all problems are simply ahead of you, but they probably sucked hard at first. you need to grind proofs at least for a few months before you can decide that you "chose the wrong field". I recommend linear algebra or basic group theory instead of analysis to become acquainted with proofs though.

>> No.12430074
File: 70 KB, 1350x1176, Drawing.png [View same] [iqdb] [saucenao] [google]
12430074

I'm looking for a seminorm whose unit ball has this kind of shape.

Any ideas?

>> No.12430283
File: 198 KB, 2356x1403, Heh.jpg [View same] [iqdb] [saucenao] [google]
12430283

How do I find the number of un-ordered subsets of size N in a set of size M? I intuit that it relates to the nature of euclidean space. It's also interesting that the solution for N=2 is generally (M-1)M/2 which is the sum of the first M-1 integers!

>> No.12430308

>>12430074
The length of a vector is the amount you need to dilate that shape by in order for your vector to lie in the dilate.

>> No.12430310

>>12430283
I think I have found a recursive form! The degree of N corresponds to the power of the polynomial of growth!

>> No.12430325
File: 384 KB, 800x1131, 1607353790825.jpg [View same] [iqdb] [saucenao] [google]
12430325

>>12430283
>unordered subsets

>> No.12430331

>>12430325
Pedantry gets degree
Autism speak sets you free

I think I discovered a general explicit form too using integrals on the recursion, I'm too lazy to compute it though. Can you check my work that this is the correct series for N=3?
1
4
10
20
35
56...

Interesting that 3 starts off more constrained than 2 but then blows up faster. Groups of size 3 don't fit as well in small space but allow for more creativity - they have more options when there is room in larger space

>> No.12430343
File: 126 KB, 1074x326, Bill Dubuque.png [View same] [iqdb] [saucenao] [google]
12430343

Bill Dubuque

>> No.12430558
File: 78 KB, 689x407, cumtrapz octave.png [View same] [iqdb] [saucenao] [google]
12430558

>cumtrapz
wtf i love numerical analysis now

>> No.12430560

>>12430558
Also:
>trapz(x, y)

>> No.12430588

Would the category of isomorphism classes finitely generated modules be small in general? Do you know any conditions for the ring that would be needed?

>> No.12430603

>>12430343
>Bill Dubuque
https://en.wikipedia.org/wiki/Macsyma
Bill Dubuque

>> No.12430655

>>12429914
Seconding >>12429945 the first proof based course often tears people up, especially if it's Rudin style analysis. Give yourself more time before deciding you're stupid

>> No.12430660

>>12430603
(indefinite integration, limits, power series, number theory, special functions, functional equations, pattern matching, sign queries, Gröbner, TriangSys)

>> No.12430665

>>12430588
Well every finitely generated module over a commutative ring R is isomorphic to a quotient R^n/Q with Q a submodule of R^n.
Using that, it looks pretty easy to prove that it's a small category.

I haven't worked that much with non-commutative rings, so I don't want to say something wrong, but the argument can probably be adapted to that case.

>> No.12430671
File: 93 KB, 800x600, aoe43.jpg [View same] [iqdb] [saucenao] [google]
12430671

>>12430665
Thank you very much my friend. I was expecting all the replies to be something like:
>algebra
dilate tranny
You have a nice day or evening or whatever it is in your country right now!

>> No.12430675
File: 104 KB, 647x478, 1595188917036.png [View same] [iqdb] [saucenao] [google]
12430675

>notation for a set to be normal in a group is the same for the notation for a set to be an ideal in a ring

>> No.12430684

>>12430675
Being a normal subgroup = being the kernel of a homomorphism of groups. Being an ideal = being the kernel of a homomorphism of rings.

>> No.12430698
File: 76 KB, 600x800, watford.jpg [View same] [iqdb] [saucenao] [google]
12430698

is [math] (R,-) [/math] a non-associative magma?

>> No.12430704

>>12430684
still dumb.

>> No.12430728

>professor won't let us download the video lectures

why

literally MIT and so many other universities just let all of their stuff be open source, commons license, whatever the fuck it is. why does my mid tier little uni object to me having video lectures a personal reference. It's obviously not me in the lectures so why does anybody care

>> No.12430735
File: 280 KB, 900x600, maths-min.png [View same] [iqdb] [saucenao] [google]
12430735

>>12430728
they hate you and want you to suffer

>> No.12430738

>>12430704
if you feel like there's anything weird about this, you should probably stop pursuing math

>> No.12430739
File: 6 KB, 225x225, 1503009808695.jpg [View same] [iqdb] [saucenao] [google]
12430739

>>12430728
>tfw yoinked the entire course shell and webex uploads before it went down

>> No.12430742

>>12430738
i get the similarity, i just don't like sharing the notation. same with principal ideals being like (a). just makes shit involving polynomials a pain to read. use angle brackets and now it looks like cyclic groups.

>> No.12430783

>>12430698
If it makes sense to ask if it's a magma and it isn't a category then it's a magma.

>> No.12430894

>>12430698
Yes. More specifically, it's a loop.

>> No.12431234

its over, scholzecels
http://www.kurims.kyoto-u.ac.jp/~motizuki/Explicit%20estimates%20in%20IUTeich.pdf

>> No.12431263

>>12424218
I do not understand fourier transforms bruh

>> No.12431282

>>12430728
If nothing else works:
Use ffmpeg with screen and system audio as the device to record from, and go full screen.
You are probably breaking implicit or even explicit rules of your uni there, though, so better watch out!

>> No.12431289

I don't understand idiots bruh, what part don't they get, the swapping frequency and time part, the differentials, the convolutions?

>> No.12431291

>>12430742
>i get the similarity, i just don't like sharing the notation
They're both (essentially) congruences in the sense of universal algebra. Now your autism can rest easy because they're literally the same thing.

>> No.12431295
File: 25 KB, 395x474, 1547971670855(2).png [View same] [iqdb] [saucenao] [google]
12431295

>teacher keeps talking and talking but in the end says nothing

>> No.12431305

>>12431295
In what maths course does that happen?

>> No.12431309

>>12431305
videocall class

>> No.12431315

>>12430665
You can do the same thing with any variety of algebras, including modules over noncommutative rings. A finitely generated algebra is going to be (isomorphic to) a quotient of the free algebra F in your variety on countably infinitely many generators. There are typically quotients of F which are not finitely generated, but in any case F can only have a set worth of congruences and hence there are only a set worth of finitely-generated guys, up to isomorphism.

>> No.12431329

We are given an ODE z''(x) - z(x) + 2g(x) = 0

I end up through rearranging and using fourier transforms with F[z]/F[x] = 2/(1 + s^2)

But there is no equivalent to multiplication and convolution, for division right? Or I might just be setting this up wrong

>> No.12431332

>>12431329
F[z]/F[g] i meant

>> No.12431365

>>12431234
Mochizuki's "proof" of ABC is a failure.

>> No.12431396

>>12431291
are there other notions that share this congruency?

>> No.12431412

>>12431295
i'm a teacher and i do that

>> No.12431471

Can i ask career questions here?

>> No.12431476

>>12431396
Basically anything you quotient out by in algebra corresponds to a congruence. So in addition to normal subgroups and ideals you also have submodules and subalgebras (in the sense of an algebra over a ring). Congruences of semigroups come up in the theory of string rewriting systems.

>> No.12431498

>>12431476
neat, thanks.

>> No.12431562

What are some books that (at least try to) answer what mathematics are?

>> No.12431574

>>12431562
you don't know what is mathematics? i'm pretty sure 7-year-olds know that, you don't need a whole book to understand that word

>> No.12431590

>>12431471
You can, but no one here's an actual tenured professor, so you won't be getting any advice from people who have actually made it.

>> No.12431604

>>12431590
>no one here's an actual tenured professor
This, I'm a postdoc and that's about the max level on /sci/ right now. Check back in 2030.

>> No.12431675

>>12428386
Anyone dares to try? I'm curious.

>> No.12431723
File: 37 KB, 146x186, UKP9Ld5.png [View same] [iqdb] [saucenao] [google]
12431723

>>12431234
ok here's what i don't understand:
here's a paper of mochizuki and 4 of his friends, and supposedly there are more people working on iutt, let's say at least 20 of them
did those people also read the entirety of iutt and they believe it all works out?
or do they try to prove results using iutt as a black box?
or did they just jump on the bandwagon of a new memetheory and believe that mochizuki has his shit worked out?

>> No.12431754

>>12431675
It's probably false, but a counter-example would probably be non-measurable (solid intuition), and constructing non-measurable functions is a tremendous pain in the ass.

>> No.12431923
File: 256 KB, 888x499, 1602867124910.jpg [View same] [iqdb] [saucenao] [google]
12431923

>> No.12431973

>it's another french visiting professor

GOD I hate europeans, specially the French, so much. They ALWAYS have fucked up hair, stench of milk and have an insufferable personality.

>> No.12432115

If all you need for linear algebra is high school level algebra why is it usually taken after Calculus

>> No.12432227

>>12431973
>stench of milk
what does that mean

>> No.12432229

>>12432115
in my undergrad we took linear algebra in first and second semester

>> No.12432244

>>12431604
>I'm a postdoc
What's your field?

>> No.12432255

>>12432115
...but calculus is a high school subject.

>> No.12432278

>>12432255
That doesnt change my question m8
Why is linear algebra often taught after Calculus

>> No.12432282

>>12432244
the one with a brown cow and some grass in

>> No.12432285

>>12432282
ah, that's the one with the naked faggots sucking each other off.

>> No.12432298

>>12432285
yeah I dont know why your dad and your brother come to my field to do that

>> No.12432310

>>12432298
Why to respect the local custom, of course.

>> No.12432373

>>12432310
guess ill see you there too tomorrow then

>> No.12432395

>>12432373
Cool. I will bring my faggot stomping boots.

>> No.12432531

Wtf is happening in this thread.

>> No.12432862

is there a "canonical" definition of pi that is grounded in number theory? i.e doesn't rely on the "geometric circle"

>>12432115
because (one can say that) everything you've learned in highschool math thus far was to build up towards the result of finding derivatives of polynomials.

lin alg as a continuation offers no real major results, whereas calculus, the definition of the limit, and the fundamental theorem of calculus would probably be among the first major results of anyone's math education, and allows one to begin a serious physics course

>> No.12432929

>>12432862
>lin alg as a continuation offers no real major results

Omfg lol.

>> No.12432934

>>12432862
i'd argue vectors and matricies are far more useful to the 'normal' persona than calculus is.

>> No.12432948

>>12425020
the dover version has extensive commentary on phrases like this. are you reading that version?

>> No.12432956

>>12432929
nothing comparable to derivatives and integrals in a first semester imho

>>12432934
the most obvious usage of vectors is vector calculus in physics; i do not see any immediate and interesting results, asides from maybe neural nets, which require the chain rule anyways/...

>> No.12432984 [DELETED] 
File: 136 KB, 840x632, 96-960073_artist-needed-cigarette-earth-pony-oc-oc-cartoon.png.jpg [View same] [iqdb] [saucenao] [google]
12432984

>>>/bant/11771766
Tooker's having an episode

>> No.12433070

>>12432984
nice

>> No.12433082

>>12432984
One of these days, I'm going to make you know that this post post was far less satisfying to you than you thought it might be.

>> No.12433093

>>12433082
Are you saying the bant thread poster is an impostor

>> No.12433143

Guys I'm really scared I'm gonna fail my metric spaces and topology exam. How do I learn this shit in a week.

>> No.12433354

>>12431305
Random Signals and Noise

>> No.12433390

>>12433143
Just play with ur balls haha

>> No.12433422

>>12433390
Kek. But I'm still gonna fail lmao

>> No.12433837

is Lie groups and representation theory a good course for the last year of my yundergrad? it is a course of the graduate course in theoretical physics but seeing its syllabus it's purely a maths course, also i should have all the requirements

>> No.12433845

>>12433837
i should point out that i have taken abstract algebra (up to galois theory), some algebraic topology (singular homology, homotopy groups) and basic differential geometry (mostly of curves and surfaces but also some general results)

>> No.12433868

>>12433422
you deserve to fail for not having paid attention, retake the course

>> No.12434033

Is there ever anything good on the ArXiv math.GM tag? Most of what I'm seeing are retards who think they can prove the Riemann with elementary complex analysis or articles on pedagogy.

>> No.12434041

>>12433837
take the course, Lie groups are general knowledge

>> No.12434160
File: 25 KB, 306x464, 978-1-4612-0927-0.jpg [View same] [iqdb] [saucenao] [google]
12434160

I'm into arithmetic geometry and a friend of mine is into logic, so I thought it would be fun to study topos theory together, and see the interaction between our respective fields.

Is pic related a good textbook for such an endeavour?

>> No.12434180 [DELETED] 

>>12434160
I don't know the first thing about arithmetic geometry but there's certainly a lot of things in that book that have little to do with it.

>> No.12434187

>>12434160
I don't know the first thing about arithmetic geometry but there's surely a lot of things in that book that have little to do with it.

>>12433837
There's a /sci/ reading group on matrix Lie groups using Hall's book

>> No.12434219

>>12434187
I don't mind learning some logic for now, and maybe later I'll read more about the cohomology theories that use topos theory on my own.
That being said, do you know a topos theory book that has a better balance between algebraic geometry applications and logic ones?

>> No.12434261

>>12434219
No it's probably fine and reasonably balanced, try it.
Most of the book I'm aware of are much more logic oriented than it.

>> No.12434763

>>12433868
Bro I attended all the lectures and I understand the concepts. I'm just too pea brain to grasp writing my own proofs from scratch.

>> No.12434922

Is the Touhou paper worth reading?

>> No.12435041

>>12434922
Link to that?

>> No.12435047

>>12435041
https://en.wikipedia.org/wiki/Grothendieck%27s_T%C3%B4hoku_paper

>> No.12435059

>>12435047
Oh, I thought it was a paper made by the Touhou poster.

>> No.12435274
File: 1.43 MB, 849x1032, 1515268810481.png [View same] [iqdb] [saucenao] [google]
12435274

I want to learn combinatorics but I'm also new to formal proof-based math (hardest math I've taken was cookbook linear algebra for college credit, senior year of high school).
Can anybody recommend a combinatorics book that starts from the basics, the way I've seen algebra and analysis books start with the definitions of sets and unions etc.

>> No.12435279

>>12435274
why do you want to learn combinatorics?

>> No.12435283

>>12435279
it looks fun and helps people solve games like poker or puzzles

>> No.12435319

>>12435279
also, I want to make my way to graph theory

>> No.12435552

>>12435274
Stanley's Algebraic Combinatorics

>> No.12435579

>>12435319
For intro graph theory use West.

>> No.12435619

>>12434922
>>12435047
I think it is for historical purposes, but if you're trying to learn homological algebra, go for Weibel.

>> No.12435681

>>12434922
>>12435047
>the Touhou paper
I'll admit I laughed.

>> No.12435805

Is there any relation between probability and measure theory?

>> No.12435853

>>12435805
Probability is about probability measures on measurable spaces. Random variables are measurable functions with respect to such a measure.

>> No.12435855

>>12435805
probability theory is literally a subfield of measure theory. measure theory is about assigning a number (an abstract volume) to subsets of some space. in probability theory, this space is the set of all possible outcomes, an event is some collection of outcomes, and probability of the event is simply its measure.

>> No.12435886
File: 610 KB, 805x720, cmMu4MI.png [View same] [iqdb] [saucenao] [google]
12435886

>>12435855
this
and measure theory is literally a subfield of set theory, since measure spaces are defined in terms of sets and measures is a function and functions are relations which are also sets

>> No.12435928

>>12435853
>>12435855
Thanks anons.
I was reading some elementary probability and Kolmogorov axioms reminded me of measure theory.
Is there any other application of measure theory outside of probability and geometry?

>> No.12435935

>>12435928
Ergodic theory, lol.

>> No.12435936

>>12435886
I usually like your posts okay, but this one doesn't really add much...

>> No.12435938
File: 912 KB, 2297x2038, 20201208_141610.jpg [View same] [iqdb] [saucenao] [google]
12435938

You just find the initial and final energy and set them equal to each other to solve for velocity right? I keep getting an imaginary number in my answer.

>> No.12435986

>>12435938
bro this is the maffs thread

>> No.12436000

>>12435986
Physics is basically the same thing

>> No.12436010

>>12435938
Idk i did that shit like 3 years ago. No fucking clue. That's highschool stuff mate.

>> No.12436044

>>12435938
I got 3.13m/s might be regraded though ngl

>> No.12436075

>>12425641
>>12425650
No, she works for Admiral Overseas Corporation and makes computer monitors for the poor using science she learned from /sci/

>> No.12436080

>>12435936
He's shitposting, literally everything other than synthetic geometry and logic is a subfield of set theory, by this logic.

>> No.12436115

>>12436044
What equation did you use?

I set E = .5iw^2+.5MaV^2+Ma*gh-(.5Mbv^2+Mb*gh)

Do you just subtract the energy of the B mass from the total mass since the system is going in the direction towards A?

>> No.12436205

>>12424218
https://www.math.ucla.edu/~jerryluo8/teaching/Winter2020-33A/The%20Manga%20Guide%20to%20Linear%20Algebra.pdf
think you guys might be interested in this

>> No.12436250

>>12436080
I think it was sarcasm aimed at making fun of the "probability is a subfield of measure theory" assertion.

>> No.12436374

>>12436250
...that's what I said.

>> No.12436385
File: 32 KB, 1425x153, blocks_your_path.png [View same] [iqdb] [saucenao] [google]
12436385

>>12424218
wat do?

>> No.12436435

>>12436385
WHat have you tried?

>> No.12436441

>>12436385
It's immediately obvious from the definition of multiplication.

>> No.12436468

>>12436385
It's not true
Let A=
[1 0
0 0 ]
B=
[0 0
0 1]
Then AB=0 but tr(A)=tr(B)=1

>> No.12436564
File: 71 KB, 753x1024, banach2.jpg [View same] [iqdb] [saucenao] [google]
12436564

>>12436435
>>12436441

>> No.12436579

>>12436250
I don't think that's warranted at all. Maybe I'm retarded, but until I understood what a measure space was I always found finite combinatorial probability problems ill-posed since it seemed like you had to learn some implicit information about the problem to answer correctly. It turns out I was right and that most of the difficulty of basic probably is that you're not given the actual probability measure in question and have to intuit which one the author means. This is also why Monty Hall and other stupidity exists.

>> No.12436614

>>12436385
Anonku, okłamali cię, weź macierz I, wtedy tr(I)=n, ale I=I^2 i tr(I)tr(I)=n^2.

>> No.12436724

>>12436080
>by this logic
I disagree, measure theory is really native in set theory, wheras anything algebraic (while having models in a theory of sets) is not essentially set theoretical.

>> No.12436787
File: 3 KB, 375x132, eq.png [View same] [iqdb] [saucenao] [google]
12436787

I am trying to solve the ODE that's in the first line. I solve it as a Riccati's equation for y=1.

The second line is the end result.

How am I supposed to proceed? Have I done something wrong?

>> No.12436793
File: 3 KB, 383x167, correct.png [View same] [iqdb] [saucenao] [google]
12436793

>>12436787
ignore the first image, this is the correct one

>> No.12437469

>>12431675
>>12428144
i googled around and found this
https://www.ams.org/journals/proc/1990-108-02/S0002-9939-1990-0987607-1/S0002-9939-1990-0987607-1.pdf
if you look at the beginning of the proof of theorem 2.4 there should be a theorem of kolmogorov and vercenko which gives you a negative answer
sadly the reference only says "chapter ix in a book lmao" and the chapter is 50 pages long http://matwbn.icm.edu.pl/ksiazki/mon/mon07/mon0709.pdf
on the positive side, it appears that the topic of "take arbitrary function or continuous function R^n -> R and look at slopes" has been extensively covered by various people about 80 years ago so you should be able to read this if you care enough
personally i give up

>> No.12438222

Where's the Finnish algebra tranny?

>> No.12438400
File: 168 KB, 1092x859, you must be joking mr rudin.png [View same] [iqdb] [saucenao] [google]
12438400

>open analysis textbook
>see this bullshit
wtf hahaahah

>> No.12438537

>>12438400
What’s the problem?

>> No.12438545

Is it true that the following function forms a bijection between the power set of Z+ and the infinite cartesion product of {0,1}:

For each element p of P(Z+), define f(p) to equal an infinite string of 0s, where the nth 0 is replaced with 1 if n is a member of p
>>12438400
Same

>> No.12438763

>>12438545
What have you tried?

>> No.12438799

I have finished with my study of irrational numbers and now I will be moving on to setless groups. These are groups that do not have an underlying set structure.

>> No.12438869

>>12438763
The question was to find a bijection and the function is my attempt at answering it, I'm asking to check my work. The idea is that ti's obviously injective and it's surjective because you can generate any order of 0s and 1s in the string.

>> No.12438902

>>12424218
Do people at your school fail out of the math major? How does it usually happen? I'm just in my first year but idk if I'm gonna make it

>> No.12438916

>>12438902
In my school we have a math major with Down's syndrome. I think he's doing pretty well.

>> No.12438918

>>12424233
Dubs confirm
>>12424355
Dubs. Anon speaks the truth. If you're learning maths for fun you should study that you want. Best way to do this is search "field I want to study pre reqs" and then find books on those to build up background. Happy studying! :)
>>12424433
No love for number theory or probability? Also dubsdubs :0
>>12424500
A lot of people start off with munkres first. It's a nice read. Dubs.
>>12424533
Thank you anon, have a good day! Dubs.
>>12426177
Dubs of truth.
>>12427022
Dubs. I also like \phi.
>>12427955
Please don't be sad, dub poster :(
>>12428144
Dubs.
>>12428255
My combinatorics isn't that great, but I'll give it a go! (dubs)
>>12428566
You're in luck, plenty of gay autismo who study maths! (dubs)
>>12428644
Should there be a space between the equations? (dubs)
>>12428700
Based computer scientist. Also dubs.
>>12428977
Last year of undergrad :( (dubs)
>>12430588
Dubs.
>>12430655
Agreed. Everyone in mine found it very difficult but after the first month everything became a lot easier! (dubs)
>>12432244
Dub dubs.
>>12432255
Dubdubs.
>>12433422
Sorry anon. Learn the bare minimum so that you can reproduced proofs on your own. Is it an online exam? Dubs.
>>12434033
Dub.
>>12434922
Dubs
>>12435855
I love measure theoretic probability! Also dubs.
>>12436000
Trips! You can't say physics is maths when the question you've posted doesn't involve proving any propositions.
>>12436044
Thank you anon for your hard work :) (dubs)
>>12438222
Trips! Who?
>>12438400
Dubs.
>>12438799
Dubs. What book are you planning to use for set less groups?

>> No.12438924

>>12438918
>What book are you planning to use for set less groups?
By reading a book on setless groups I would be robbing myself of the joy of discovering the theory on my own.

>> No.12439147

Lets say I have a Markov chain [math] X[/math] with state space [math] S=\{1,2,3,4,5 \}[/math] and transition matrix [math] P[/math],
how can I calculate [math]\mathbb{P}[X_k = j_k, X_l = j_l | X_m = j_m][/math] without using the law of total proability a lot of times? Doing that way seems rather awful?
For example, suppose that I have [math]\mathbb{P}[X_{10} = 1, X_2 = 2 | X_6 = 3][/math]. I'd have to use it 7 times which is truly a pain in the ass having to calculate

>> No.12439170

>>12439147
Idk do like the P^10 thing

>> No.12439252

>>12424218
What kinda undertale OC shit is that and what does it have to do with maths

>> No.12439254

>>12439170
I thought about that too but the problem is that in that way I'm taking "all the paths" insteads of the paths that go through a certain state

>> No.12439439
File: 81 KB, 202x289, sage.jpg [View same] [iqdb] [saucenao] [google]
12439439

found a potentially useful image

>> No.12439484

>>12431263
just a dot product except with infinite vectors
infinite sums become integration, so its an integral
your basis vector is [sin(x),cos(x),sin(2x),cos(2x)] etc, and that's strange, but it really just is a dot product.

>> No.12439548

>>12438902
usually people just swap over to something easier
one girl swapped to comp sci

>> No.12439580
File: 115 KB, 725x987, 64p9v.jpg [View same] [iqdb] [saucenao] [google]
12439580

>>12438222
Here. Why?

>> No.12439744

>>12439580
Hi! Have you been busy? No arxiv links or things like that for ages.

>> No.12439757
File: 263 KB, 1920x1080, apssu.jpg [View same] [iqdb] [saucenao] [google]
12439757

>>12439744
Hiya! Not really busy, just dead inside and stuff. If you people want me to, I can spam some papers every morning, but otherwise I'll let you be in peace.

>> No.12439853
File: 4 KB, 500x78, JZxZdLegHD-numberline_integera1[1].png [View same] [iqdb] [saucenao] [google]
12439853

If |a-b| <= |b|/2 then a and b have the same sign.

That's a cool trick. I can see why but it wasn't immediate for me.

>> No.12439878

Anyone's got an algebraic formula for both branches of complex square root?

>> No.12439939

>>12438400
>wtf hahaahah
That looks completely standard.

>> No.12439943

>>12438400
imagine being filtered this hard

>> No.12440213

>>12430325
Is this from Disgaea?

>> No.12440232

>>12431562
None
Maybe >>>/lit/
This board does not care about what mathematics are, is about doing mathematics

>> No.12440244

Does Artin's Algebra require any LA background?

>> No.12440263
File: 9 KB, 1024x1024, tibia classic.png [View same] [iqdb] [saucenao] [google]
12440263

What are the best Universities in regards to their research into the areas of algebra and representation theory?
Is it the usual suspects, MIT, Princeton, Oxford?
I'm thinking of where to apply for a postgraduate position

>> No.12440271

>>12440244
No.

>> No.12440311

>>12440263
You should delete this thread before it gets banned, because posts like these strictly go on /adv/

>> No.12440313
File: 171 KB, 1080x1081, Dllds.jpg [View same] [iqdb] [saucenao] [google]
12440313

Someone help me

>> No.12440335

>>12440313
What have you tried?

>> No.12440354

>>12440313
Nothing. Can't understand my teacher's discussion due to slow internet connection.

>> No.12440383

Any ideas?

[math]y(x)=5+ \int_{0}^{x} (t^2-2y(t))\,dt[/math]

>> No.12440387

>>12440383
Derivative & FTC

>> No.12440527
File: 157 KB, 1280x1106, 7ph4u.jpg [View same] [iqdb] [saucenao] [google]
12440527

>>12440232
What is your favourite mathematic?

>> No.12440528

>>12430283
>number of (unordered is redundant) (sub)sets of size N
wouldn't it always be N!

>> No.12440651

>>12440313
Can you guys provide some video link for these lessons...please

>> No.12440717

>>12440528
That would imply that the number of subsets of size 2 in a set of size 100 is 2!

>> No.12441071

How do I show that if y solves the ODE y' = sin(x+y), that the limit of y is -\infty? It's obvious from the slope field, but that's not very rigorous. I know the solution is tan(x+y)-sec(x+y)=x+c but I'm not sure how that helps.

>> No.12441154 [DELETED] 
File: 71 KB, 562x650, 1603381328259.jpg [View same] [iqdb] [saucenao] [google]
12441154

Let a be a real number. Let f:R==>R and lim _x-->a f(x) = infinity. Then the limit lim_x-->a cos(f(x)) DNE. How do I prove this? I know to go by contradiction but can I use the sequential criterion?

>> No.12441184

>>12440313
>(a)
It tells you what the rule is, just apply it. [math]R=\{(2,6),(3,6),\text{ etc. } \}[/math]
>(b)
again, it tells you the rule. just apply it with those values.
>(c)
Recall the definition
>(d)
Recall the definition.
>(e)
Refer to question 2 for an example.

>> No.12441191
File: 135 KB, 1080x1069, IMG_20201210_024218.jpg [View same] [iqdb] [saucenao] [google]
12441191

>>12426628
Thanks man, i figured it out. Can you help with b part here?

>> No.12441197

>>12441184
Wrong reply above lol

>> No.12441208

>>12441191
C'mon man, this is sad. Do you know what the definition is for domain? Do you know what [math]F(x)[/math] means? Have some initiative.

>> No.12441213

Hi math gods. In another thread someone showed me the Michael Penn video of why analysis doesn't work on the rationals because for example the rational function f(x)= 1 if x <sqrt(2) and 0 if x>sqrt(2) is continuous at every rational number q but does not look continuous, i.e. has a jump at sqrt(2).
I pointed out that this could be fixed if you reformulate the condition to continuity by saying that f:Q->Q is continuous if for every rational Cauchy sequence (x_n), the sequence f(x_n) is also Cauchy. I think this definition fixes the issue and the function f becomes discontinuous, but people in that thread keep claiming I am wrong and I don't understand their reasoning.
Can anyone explain how I'm wrong?
Also can anyone explain why reals are necessary for analysis, like give examples which don't work if you only work over the rationals?

>> No.12441222

>>12441154
Without assuming f is continuous, this is incorrect. There are functions f such that lim_x->a f(x) = infinity but lim_x->a of cos(f(x)) exists.

>> No.12441254

>>12441208
Yeah it's sad. I didn't understand the lesson cause of our internet connection

>> No.12441262 [DELETED] 

>>12441222
Can you give me an example of such a function?

>> No.12441264

Is there any term fo a multiplicative group of matrices whose absolute value of determinant is 1? ([math]M \in GL(n, R) \wedge |\det M|=1[/math])

>> No.12441266

>>12441262
I can.

>> No.12441267

>>12441213
write a formal proof please.

>> No.12441271

>>12441208
Oh shiii. I figured it out. Thanks btw

>> No.12441275

>>12441264
Yes. It's called the "shit group of irrelevant
matrices".

>> No.12441276

>>12441213
https://math.stackexchange.com/questions/2855609/prove-or-disprove-if-x-n-is-a-cauchy-sequence-in-x-and-f-is-a-continuou?rq=1

>> No.12441280

>>12441213
>Also can anyone explain why reals are necessary for analysis, like give examples which don't work if you only work over the rationals?
IVT, mean value theorems, bolzano-weierstrass etc. all of this is becomes false and it's just baby stuff

>> No.12441281

>>12441267
Formal proof of what?

>> No.12441285

>>12441264
the group of volume preserving linear transformations

>> No.12441287

>>12441264
the group of prolapsed anus

>> No.12441302

>>12441275
Is group that contains special linear and orthogonal groups really so irrelevant?

>> No.12441303

>>12441276
Thanks but I don't see how this is relevant to what I said.
>>12441280
These theorems become false as usually stated because we're no longer dealing with real numbers, but I think there are simple modifications that are very similar that give you all you want in applications, no?
For example, instead of saying you can find a zero in the IVT, you say you can find a Cauchy sequence whose values approach 0, and so on.
It seems to me like the real numbers are used to "forget" important information about sequences to perhaps make the statements a bit simpler but it comes at the cost of making things uniform which should not be viewed as uniform. This comes at the cost of making the theory much more computationally obtuse and obscure.

>> No.12441358

Say I have a rational number p/q. What's a good algorithm to find the best rational approximation a/b to p/q such that |a|, |b| < M for some natural number M?
For example, I would like to approximate 100000001/200000000 by 1/2, even though they're not equal, to save space.

>> No.12441369
File: 757 KB, 1216x720, Z4CJbo5.png [View same] [iqdb] [saucenao] [google]
12441369

>>12441358
continue fractions solve the problem "what is the best rational approximation p/q to a real number x, under the constraint q<N" where N is a number of your choice
the algorithm takes log(N) steps on an average real number so it's pretty good

>> No.12441374

>>12441266
Okay, what is it? I've already tried everything I can think of. I can't come up with something but I keep getting an essential discontinuity or oscillation.

>> No.12441375

Do you study crystal tilings? I feel like they're planar permutation groups

>> No.12441379

>>12441374
a=0
f(x)= 2pi * floor(1/|x| ) at x!=0
0 at x=0
Then lim_x->0 of f(x) = infinity
but lim_x->0 of cos(f(x)) = 1

>> No.12441389

>>12441303
I think you should work through some analysis textbook, and then do it again but formulate everything via cauchy sequences. that's the only way you'll find your answer.

>> No.12441402

>>12441379
Thank you anon. I feel stupid now.

>> No.12441407

>>12441402
Mathematicians get to enjoy feeling stupid much more often than normal people. Get used to it.

>> No.12441413

Found a very good article about exactly what I was wondering about
https://www.dpmms.cam.ac.uk/~wtg10/reals.html

>> No.12441450

what series is this?

[math]1-x+x^2-x^3/3+x^4/24[/math]

>> No.12441467

>>12424218
So I applied for a trading internship a few days ago and they have now asked me to do a quantitative reasoning test. Is this going to be similar to the GRE section do you think? How could I prepare a little bit?

Probably not too relevant to this thread but thought I'd ask.

>> No.12441483

>>12441450
isn't the 3 supposed to be 6?

>> No.12441489

>S. So a moral you could draw is that when most mathematicians talk about the real numbers, they don't know what they are talking about.

>L. That's a rather blunt way of putting it. I'd prefer to say that they leave unspecified what they mean by the idea of an arbitrary subset of a set, because they don't need to worry about it. They have the axioms for a complete ordered field, and if you believe in the external reality of mathematical objects then you will have to say that those axioms are ambiguous, because the completeness axiom relies on the notion of an arbitrary sequence, which is not fully explained. But if all you want from your axioms is a set of rules for when you are allowed to deduce one mathematical statement from another, then the axioms for a complete ordered field give this to you.

Tim Gowers is in agreement with Wildberger, so it seems.

>> No.12441504

>>12441483
no

this is from a picard iteration for n=4

>> No.12441518

>>12441450
And a /2 with the x^2 and an ellipsis? Otherwise it's just a quartic equation

>> No.12441543

>>12441450
[math](1,-1,1,-1/3,1/24,0,0,0,0,\dots)[/math]

:)

>>12441489
That's overshooting, since Wildberger wants to pursue people not even use R.

>most mathematicians talk about the real numbers, they don't know what they are talking about.
Sure, that's almost a given. Whoever you are, if you study foundations proper, you end up with some itching conviction that most people who don't care don't want to hear. Logic people "go crazy", which is not to say anything bad about them. Crazy is just different than the rest who don't even know about it. Most mathematicians just want to find a topic they like, marry some woman and live to their death proving theorems in their subject, not worrying "what it is they do" beyond the subfield of math they are good at.

>> No.12441574

>>12441413
Great read, loved the reference to Richard's paradox.

>> No.12441642

>>12441264
Special Snowflakes

>> No.12441659

>>12441656