/sci/ - Science & Math

gööh

täätä

>>9561822
>Anime edition
You mean regular /mg/?

Hello what do you think of anime

>>9561849
Waste of time, but pic related is a good way to decorate your room for optimal mathematical efficiency.

>>9561852
Lots of useless things there. Must be an algebraist's room.

>>9561857
The animals are necessary.

>>9561861
They're contractible so no, they're not necessary.

>>9561878
>contractible
They have tubes going from their mouths to their butts. Are you sure they are contractible?

>>9561857
you can tell it's not an analyst's room because it doesn't look like a hurricane just tore through it

>>9561894
>They have tubes
Animal plushes do? Since that's what was in the room you posted.

>>9561901
My polar bear eats raisins.

>>9561905
Does the category of bears admit a faithful functor from the category of berries such that it's surjective on the subcategory raisins into the subcategory of polar bears?

any of you guys good at math but absolutely blow at physics?

the solution to almost every problem feels like just having memorized the correct asspull for every situation rather than building up a consistent logical framework for breaking down problems.

>>9561920
>physics
>>>/toy/

>>9561915
I am quite sure that is the case. Although, I must admit I'm not sure how he eats them. I will get some and do some category theoretical research on this matter.

>>9561929
Sorry but feeding your animal without proving the existence of that functor is animal abuse. I'm calling PETA right now.

>>9561940
Attacking me is a choice, me firing back at them is an immediate consequence. I doubt they will dare come close to my home.

>>9561920
I'm not very good at physics problems either, but I think it's wrong to characterize solving them as "just memorizing asspulls."
Not everything in mathematics can be broken down into dead formal recipes either; for example integration, or the kind of problems you find on olympiads.
These sorts of things seem like dumb tricks until you've practiced enough to recognize the patterns, and then the make sense.

>>9561949
I will join you.

>>9561957
We will paint the world red with their blood.

>>9561959
They will know pain.

>>9561969
They will know fear.

>>9561975
They will know despair.

>>9561979
They will know death.

>>9561989
Not yet. They will suffer before they know death.

god I hate anime

>>9561996
They will beg for the sweet mercy of death.

>>9562001
Exactly.

>>9561996
C-can I have a raisin?

>math
>anime
Oxymoron. You don't mix intellectuals' activity and gook trash for nu-males.

>>9562007
I don't have any on me right now but I have black anal beads that look like raisins.

>>9562018
>gook trash for nu-males.
hello redd*t!

>>9562018
>yfw

>>9562045
>believing for a second this can get you a job even in CS

>>9562109

>He thinks CS is math.
>Computer Science
>Science

Kek

>>9562160
>reading comprehension problems amongst weebs: the new evidence

Threadly reminder to work with physicists.

where's that fucking faggot that was giving me shit for not making a list

>>9562262
I have many more resources I use regularly, like video lectures, lecture notes, etc that I'll supply on a final edit and I'll include more detail

>>9562262
>faggot
Why the homophobia?

>>9562262
>Linear Algebra Done Right
Why the determinantphobia?

>>9562272
/sci/mg/ Homology group of fags with homotopic gender

https://en.wikipedia.org/wiki/Homology_(mathematics)

https://en.wikipedia.org/wiki/Homotopy

>>9562272
/sci/mg/ is a Homology group of fags with homotopic gender

https://en.wikipedia.org/wiki/Homology_(mathematics)

https://en.wikipedia.org/wiki/Homotopy

>>9562276
I'm only recommending it because a lot of people had had success with it, and he has a nice lecture series to accompany it, chapter by chapter, topic by topic.

>>9562314
>recommending books based on hearsay

Are there any good anime about math?

>>9562332
Yuyushiki is about math in spirit.

>>9561915
>surjective
>not essentially surjective

>>9562338
This.

>>9561920
>>9561956
>>9562179
Refer to the "physics" threads over at >>>/toy/.
>>9562109
>>9562160
Fuck off to the "CS" threads over in the >>>/g/hetto/.
>>9562169
Your "people" are not welcome here. >>>/r/eddit/

>anime edition by the resident weebs
>literally zero math has been discussed so far

seems about right

>>9562416
Wrong website. Visit >>>/r/eddit/.

>>9562427
>muh anime website
It's a fucking imageboard for discussion of many topics. Yea shitposting and anime are fine, but you are just obnoxious after a while saying the same godamm shit over and over.

>>9562433
Obnoxious and they tend to drive out meaningful discussion

>>9562435
I suppose it's true the few people with or in a PhD are also weebs. That doesn't excempt them from constantly shitting threads.

>>9562433
>muh
Return to your home. Your "people" and your disparaging remarks about anime are simply not welcome here. >>>/r/eddit/
>>9562438
See the above message.

>>9562447
Nah, I like it here. I will keep complaining about anime until I die.

>>9562460
Keep being a redditor until you die, but do it at >>>/r/eddit/.

>>9562319
>zizek
post disregarded

>>9562463
Make me nerd.

>>9562465
What's wrong with Zizek?

>>9562319
>>9562465
>>9562472
>>>/lit/

>>9562433
upvoted my fellow redditor

How does /mg/ deal with depression?

Should I just submit and get SSRIs?

>>9562502
>Should I just submit and get SSRIs?
The usual garbage they sell to you "officially" didn't work for me at least, if you catch my drift.

>>9562409
>>9562427
>>9562447
>>9562463
>>9562485
>makes a math thread to discuss nu-male cartoons that have their own board
>get told to fuck off back to the said board
>loses shit and cries like a faggot
Come here and sip some tea, son.

9562620
>reddit frogs
Deport yourself back to >>>/r/eddit/. Your kind isn't welcome in these threads.

>>9562409
>CS isn't math
someone is a heathen

>>9562620
You seem lost. This is the math general on an anime discussion website.

>>9562641
>"every object in the topos of sheaves on a point is projective" is somehow """computation"""
Are you mentally handicapped? Fuck off to the "CS" >>>/g/hetto/.

Pic related. Obviously a simple solution, but I can't figure it out. Would the following be sufficient proof?

Conceptually I understand how the cardinality is the same, since for every ordered pair (or 'every element of the set'), there will be a corresponding n in N that it is mapped to. Where I'm lost is actually constructing the bijection, and what that process should look like.

My best attempt so far is below, but it's far from formalized.

Organize the set of all ordered pairs [math] NxN | {[(0,0),(0,1),..(0,a)][(1,0),(1,1),(1,b)]} [\math] such that set (0,0) maps to 1, (0,1) maps to 2, (0,a) maps to i, and, performing the same mapping to the latter half of the sets, (1,0) maps to i+1, (1,1) maps to i+2, (1,b) maps to i+b.

>>9562683
>[math] NxN | {[(0,0),(0,1),..(0,a)][(1,0),(1,1),(1,b)]} [\math]

[math] NxN | {[(0,0),(0,1),..(0,a)][(1,0),(1,1),(1,b)]} [/math]

>>9562684
[math] N \times N | \{[(0,0),(0,1),..(0,a)][(1,0),(1,1),(1,b)]\} [/math], where a and b conveniently represent an infinite process for me, which probably won't fly

take 3 anyhow on the latex editing

>>9562687
>where a and b conveniently represent an infinite process for me
What is an "infinite process"? Discuss CS stuff at the appropriate board.

>>9562697
weak bait. sad!

>>9562707
In what way is this "bait"?

How do I know diff forms are real. As in, how do I know it's consistent with measure theory and shit.

>>9562709
Because infinite processes are essential to all maths

>>9562724
>infinite processes
Sounds like some kind of CS gibberish which should be discussed solely at >>>/g/.

>>9562727
pls just answer my question sirs

>>9562727
take your finitist philosophy and shove it up your ass, retard

>>9562730
https://en.wikipedia.org/wiki/Pairing_function
>>9562731
Where does my post mention "finitism"? You seem to have serious problems with reading comprehension.

>>9562733
I don't wanna spoil the surprise anon-san, give me a hint

>>9562683
Oh and of those sets map up to some (m,n) set, I should've used index notation to clear things up

>>9562733
cool thanks though anon, I kinda had a primitive cantor snakey going on in my doodles but couldn't figure out the algebra of such a function, I'll probably finish this tomorrow

Is combinatorics basically discrete math for mathematicians? why do I find 'discrete math' books so unappealing?

>>9562798
>discrete "math" for mathematicians
No such thing.
>why do I find 'discrete math' books so unappealing?
Maybe you dislike programming stuff in general? It's better to ask the experts at the >>>/g/hetto/ if you want to get into it.

>>9562799
No I like programming, but I feel that the whole field is currently like calculus before analysis was invented and all the books cater to compsci fags and their applications. I guess I don't like how it immediately implies programming.

I do like Lovasz works on the topic though. I'll look around for more I guess.

>>9562799
And why is there no such thing? Most math majors have to take some class like it

Can I have some non-brainlet maths memes?

y'all know how in chem/bio/whatever, there's always this dichotomy between going into industry vs academia (i.e. that of money/selling out vs less/no money). is there an equivalent situation for mathematics, and more specifically, pure mathematics?

>>9562908
Becoming a quant?

normies get out

https://en.wikipedia.org/wiki/Ree_group

>>9562945
Stop sucking your mom's Tits and make your dad feel good, you filthy hairy ball licking Cox-Zucker machine.

>>9562938
>>9562938
hmm, do quantitative analysts really make that much? and that's not really the kind of thing for someone coming from a pure mathematics background, is it?

>>9561920
Other way 'round.
Hated PDEs. I think Prof was demonstrating how to solve a conductive heat transfer problem.
Prof said "Assume an answer in the form of such-and-such..."
(Puzzled) "Why?"
(Exasperated) "Because that's the one that works!"

>>9562985
Discuss physics at >>>/toy/.

Nice anime math thread, but OP used a dumbass as pic

How do I pick a topic for postgrad study

>>9562683
That hint is a meme. Just think about factors instead.

I never studied linear algebra. Should I skip the matrix shit and just skip to Axler book?

I'm studying book of proof too

>>9563041
Don't use Axler's book, he has an irrational fear of determinants.

>>9562899
facebook/memesofanelephant/
facebook/trivialbycategorytheory/
facebook/EInfinityRingSpectrum/
facebook/recreationaltypes/

>>9563041
study linear algebra and do not skip anything. if you're giving yourself the privilege of self-studying the subject don't move onto the next topic in the course progression until you're 99% confident you're competent enough to use what you just learned in the next chapter without being explicitly prompted to do so.

linear algebra is probably one of the most useful subjects and I genuinely wish I spent more time on it and took it more seriously when i took it

>>9562683
Just draw this and submit it as the proof.

>>9562899

>>9563166
That's not a proof.

>>9563247
You can easily make it a proof.

Can someone explain all of HoTT to me, or at least the general idea?

I've read about half of it, I still don't understand what path induction is.
How can you form a judgement about an identity type x = y solely by proving it for the reflexive type x = x?
The book calls it the induction principle for identity types.
Is the principle an axiom?

>>9563302
do you know any vanilla MLTT/CoC theories already

>>9563302
>How can you form a judgement about an identity type x = y solely by proving it for the reflexive type x = x?
It has to do with how HoTT interprets types as spaces, inhabitants as points, and identities as paths. refl_x: x = x and p: x = y end up being homotopic, so the latter must automatically satisfy all the properties of the former and thus path induction is justified. Something like that.

>Is the principle an axiom?
It is in HoTT, for now, but cubical type theory is able to compute it.

>>9563357
That's a semantic argument. I'm pretty sure they're asking for the syntactic justification.

>>9562262
nobody ever talks about this textbook but I found Contemporary Abstract Algebria by Joseph Gallian quite readable
And readable = you will actually read it

>>9563381
>they're
>>>/t/umblr/

>>9561956
>integration, or the kind of problems you find on olympiads
>in mathematics

>>9563487
Are you ok?

What is objectively the best definition of the tangent space.

>>9563540
as the dual to the cotangent space

>>9563250
How so? I am op of the problem and this is where I'm stuck. I indeed drawing the same pattern last night but couldn't map it algebraically without cheating

>>9563351
I'm allergic to vanilla

>>9563302
HoTT = ITT + UA + HIT

>>9563540
Velocities of curves when you actually want to do diff geometry. Algebraic crackery is just a tool to make shit easier so fuck
>>9563576

I want to go see a psychiatrist but I don't want to ask my parents for more money. If I make an indiegogo/gofundme for it will you guys pay for my doctor visit and prescription bill?

>>9563791
What country are you from?
Also, are you a cute girl (boy) irl?

>>9563802
I am from Romania so it won't cost that much, I think. I think I could pull off a girl (male) look since I'm skinny and only 170cm tall, but I don't have any girl clothes, so if you'd want some naughty trap pictures in exchange I'm afraid I won't be able to provide them.

>>9563813
Shave your legs and post thighs

>>9563819
ok

>>9563823
I hope you realize there are only two kinds of mathematicians: the ones who lift and the ones who crossdress.

>>9563889
your thread sucks

>>9563986
>your
What did zû mean by this?

>math general
>no math, just the undergrads too obsessed with category theory to do any math at all shitposting anime

>>9562985
That's just how analysis works, you pull all these solutions and estimates out of your ass and hope shit just werks

>>9563995
i meant exactly that

>>9564015
Please don't press the send button before your post is fully done. You sent it before writing what you meant.

>>9564022
your thread sucks

>>9564025
It's not mine. I haven't been the OP for ages.

>>9564029
post math

>>9563026
I feel like something that is being researched in mathematics that interests you can be a good topic. Applied mathematics is also a thing to look at.

>>9564036
This is the anime shitposting general, fuck off with that gay math shit already, it doesn't belong here.

>>9564036
Why?

>>9564043
yeah I guess avatarfagging in some shit general thread is exactly what this place always needed

thanks for helping make this place ass, going back to not posting here again now

>>9564063
Nice blog post. I r8 8/8

>>9564063
>yeah I guess avatarfagging in some shit general thread is exactly what this place always needed
My post was satire and I am not "avatar fagging" in the slightest.

>going back to not posting here again now
You could have posted math yourself, you know...

>>9563643
First consider the sequences of (n-i,i) as i runs from 1 to n, this obviously has n members and is distinct from all such sequences of different n values, then think about how to chain them together.
You can directly define a sequence for this by noticing that summing the number of members of the first N such sequences is the sum of the squares of naturals up to N, N(N+1)(2N+1)/6.
Then define a function that gives you a nice way to categorize integers in a way that lets you assign nice coordinates to them that work out as outlined above. It can't be very difficult.

>>9563889
They itch like crazy now. And I never realised just how tedious and time consuming shaving your legs is. Even though I may have done this for nothing, I am desperate enough to try so here is a trial photo. (I also accidentally cut myself a over a dozen times, but that felt good.)

I know it's not the best angle, and it's an old phone camera. But please, at least tell me if my legs are pretty enough for me to successfully prostitute myself for antidepressants.

>>9563540
pairs of (chart, cartesian vector) quotiented by (phi, v) ~ (psi, w) when (phi . psi^-1)'(v) = w

>>9563734
"someone explain enriched categories to me"
"do you know what a normal vanilla category is is"
"I'm allergic to vanilla"

>>9563996
as an undergrad obsessed with category theory who is currently taking a complex anal course I resent this harmful stereotype

>>9564129

>>9564129
And now you understand why the striped socks are so popular. I was going to donate you 100 euros, but I will take them back as the payment for this lesson. I tip my imaginary fedora to you, though.

>>9563643

diag diagIx numIx = (diagIx - numIx, numIx)
enumeration = [0..] >>= \ix -> map (diag ix) [0..ix]
bij n = enumeration !! n


hope this help's

>>9564129
if you are really desperate, there are universities, hospitals and clinics that have free psychiatric consults. sometimes it's in group sometimes it is for new med psychiatric students to start and get hands dirty.
ask around your uni or near hospitals/clinics. do that or stop being a sissy and tell your parents. or get a job, idk.

>>9561822
>>9561825
>>9561835
>>9561837
>>9561849
>>9561857
>>9561901
>>9561905
>>9561915
>>9561940
>>9561949
>>9561957
>>9561969
>>9561996
>>9562001
>>9563791
>>9563802
>>9563889
>>9564022
>>9564043

also, nice MATH general in the SCIENCE board btw, MODS doing their jobs i see.

>>9564152
>>>/reddit/
Besides, therapy is a scam.

>>9564148
>>>/g/hetto

>>9564162
>your foundations don't include inductive and coinductive types and recursive and corecursive functions as primitive notions
i hope u enjoy building your basic constructions out of reified predicates

>>9562416
They're a bunch of physishit avatarfags who'd love to see the general go down the drain as much as possible.

>>9564175
I'm a mathematician. Don't mismajor me.

>>9562681
you realize the yoneda lemma is named after a computer scientist

>>9564175
as feynman said, physics is to math as 3d sex is to 2d sex
and you think it's the physicists who are the weebs?

>tfw you're the only /mg/ poster without social/mental issues

>>9564180
>I'm a mathematician. Don't mismajor me.
Mathematicians use "we", not "I".

>>9564189
I'm not a schizophrenic.

>>9564152
>no more anime on 4chan

>>9564161
>>9564191
>anime-only posts on /sci/ instead of /a/

>>9564199
Delusional people go to therapy, right? Nobody said that, so you belong to the therapist's office.

>>9564199
Alright then, let's talk about math too.

sin(x) = 1/2
How do I solve for x???

>>9564152
That's not how it works here. You first have to know a guy who knows a guy. All gratuities are handed out to family and acquaintances, even though everyone is technically entitled to them. It's fucked up, but that's how society works in this eastern European shithole. The only way I can force their hand is by using my health insurance card (since then the government would pay them instead of me personally), but since I have never had a job, that one is tied to my parents. and to do use it I'd have to contact them and our "family doctor". Which brings me to

>stop being a sissy and tell your parents
If I could, I would have done it already. The fact that I am a NEET leeching off them while I'm pretending to be looking for a job is killing me right now. I quit my math grad (Master's) programme last summer (told you guys about it back then; I was just too autistic and stupid to get in touch with an advisor that would supervise my graduation thesis) and I still haven't told them about this. They think I managed to graduate. And they're beginning to catch up to the fact that I haven't been looking for a job all these months. What would they say if I contact them to tell them that I am having near catatonic episodes just doing my groceries to stay alive (even though I go to the market during off hours) and they ask why I am so fucked up mentally right now?

Sorry for the blog post, but I'm at a loss what to do. I guess I don't look feminine enough for online panhandling to work. I feel so drained right now that thinking about begging on /mg/ was the only thing that crossed my mind. I keep fantasising about killing myself, but I always end up thinking about the aftermath which pulls me out of trying it. I wish I'd die in my sleep tonight.

>>9564137
"no"

>>9564210
arcsin

https://en.wikipedia.org/wiki/Inverse_trigonometric_functions

>>9564238
Not xõr, but did you know that the "arc" in arcsin stands for "arcus" which means arch, and so arcsin turns arch length into a corresponding angle?

>>9564230
>quit my math grad (Master's) programme last summer
>I go to the market during off hours
are you me?

>>9564190
But we are.

>>9564252
We wuz but I ain't anymore.

>>9564152
mods love these threads because they keep the fuckhead attention whores away from the rest of the board

>>9564250
No, I'm not you. Why did you quit? And how are you dealing with it? Do you parents know?

>>9564230
unless you actually do kill yourself, eventually all this shit is gonna be clear to them
I'm not qualified to be giving advice but maybe you should rip off the band aid

>>9564189
The "we" is the author and the reader
you didn't mismajor yourself

>>9564265
>Why did you quit?
Finally accepted that research wasn't for me after working on two research projects I didn't care for and couldn't find anything I was genuinely interested in writing about, plus a mediocre relationship with my supervisor, plus not caring about any of my courses, plus never really having a strong desire for grad school to begin with (just going because it was easy to apply/mildly pressured by department head where I did my undergrad), and I felt like if I had submitted something I didn't care about it then it would have just felt like I had a fraudulent degree

>And how are you dealing with it?
Been a NEET since leaving

>Do you parents know?
Yes (told before I left)

Mathematician's boipuccy is made for engineer's massive cock.

It's silly to hate on CS. From a mathematical perspective, it's the wild west of possibilities. I predict this century will be a landmark for mathematical breakthroughs, largely done by the mathematical minds that will be working in that area.

Plus, the shits just cool. Automatons, automated theorem provers, hypercomputation, cryptography, etc. Though I understand hating on CS undergrads, and possibly even grads, you shouldn't bash a field because of the demographic.

>>9564238
a shitty answer to a shitty question, I love it.

>>9564339
>applied CS
absolutely disgusting

>>9564339

>>9564231
then don't try to learn HoTT until you understand, e.g.:
- propositions as types
- distinction between typing judgments and system-internal propositions
- distinction between definitional and propositional equality
- the basics of intuitionistic logic and how it differs from classical logic
- &c.

>>9564363
trust me - all of those things are tricky enough by themselves, and 90% of the things that initially seem bizarre or contradictory in HoTT require an understanding of all of those things (at least) to untangle

>>9564363
>>9564373
Add intensional vs. extensional proof to the list, that's also where paths differ from standard equality types.

>>9564381
not sure in what sense you're using {in,ex}tensional here. do you mean like proof irrelevance?

>>9564389
Well, for example MLTT uses intensional equality since every equality proof is built inductively from refl. Whereas NuPRL is extensional. HoTT is a bit of both since you have refl and path induction but also univalence and HITs.

>>9564300
I wish I was in your situation. I actually really wanted to go on and pursue a PhD. but I was too much of a sperg to actually do it. And sometimes I also fear that maybe I'm not smart enough for it, and the fact that I am autistic is just a convenient excuse to hide myself from that reality.

I almost didn't even finish my undergrad degree. Here you also need to do a sort of thesis at the end of your Bachelor's (although for undergrads it doesn't necessarily need to be original research) but I was being too anxious to talk to a professor about what I'd want to write it on. I only got saved because undergrads are more cuddled -- basically, we were split into groups and each group had a professor from the department that was a sort of 'tutor' who would check up on you to make sure that you filed your papers in time and that sort of stuff, and the guy who was tutoring my group helped me find an advisor. But during grad school I was entirely on my own.

I still think sometime that maybe I subconsciously sabotaged myself, because the professor I initially wanted to write my thesis with began to drop hints that she'd like me to pursue a PhD. under her after I would have finished my Master's, and I felt extremely intimidated by that (not so much that she was a woman, but the fact that she was very enthusiastic about it and seemed to have a lot of expectations from me) and I kept wavering until a classmate contacted her before me. She only had the possibility of supervising one more Master's student and that threw a wrench in my plans (either university or department policy limits the number of students each professor can advise, which I guess is a good practice, just not one that ended up suiting me). And then it turned out that the only two other professors that could advise me on a subject I was interested in were people whom I had never met, and I just don't know how to do cold openings. So I kept postponing, until I couldn't postpone anymore.

>>9564391
Ah, you mean intensional vs. extensional *type theories*, not *proofs*?

>>9564435
Wait, what's the difference?

And people (read retards) still say that bronies are worse than weebs...