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00:00 - 23:0023:00 - 00:00

00:19
hey @TedShifrin
 
3 hours later…
03:07
Undergraduate and postgraduate level mathematics discussion group in whatsapp.
03:23
Hello, I am working on a problem and eventually got this: wolframalpha.com/input/…. I need to know how many integer solutions for x exists (I don't care what they are). Is there any way to mathematically get the answer that Wolfram got (there are 3 integer solutions)?
Howdy @Alekos. Long time!
03:45
yeah indeed...
things have been surprisingly busy
how are things in SD?
I'm still alive?
somehow it seems rather miraculous that we're all still alive considering this world we find ourselves in...
I'm hoping to escape to greece in about a month, but we'll see how that goes.
I don't plan to travel anywhere for quite a while. I think the worst is yet to come.
So, how's your geometer's life going?
it's been pretty interesting! the first semester things were a bit slow, I "wasted" some time on some core courses, but the last few months have been very productive.
I've been learning some hodge theory, some characteristic classes, some bona fide algebraic geometry and some other odds and ends.
I recently learned a proof of Chern-Gauß-Bonnet, which I was pretty happy about.
04:00
Wow. If I remember any, we can discuss some serious math!
I should send you my complex geometry exercises from years ago.
you already have, actually!
it's been on my mind to do some of them at some point.
Maybe you can peer pressure me into doing some LOL
Oh? :)
I've been organizing some seminars with friends to keep ourselves productive, so more of my time has been going into preparing talks.
I need to do more exercises.
It's pretty stressful these days, because it feels like I need to learn 1000 things this summer, and of course there is not sufficient time.
04:04
My favorite Gauss-Bonnet proof (without boundary) uses independence of connection and reduces to submanifold of $\Bbb R^n$ and uses Grassmannians and what Schubert cycle the Euler class is dual to.
Giving talks to learn is great.
I don't think I know of that proof, sounds pretty hands on (in a good way)
I can send a scan if you want.
I've not seen it in any book.
Sure, that'd be great. I can't promise to read it in too much detail in the next few days, but I'll definitely take a look.
You know chern-weil that the cohomology class is independent of connection?
Yeah, the proof I learned for CGB was via chern weil theory.
04:07
Email me with your e-addy.
You're doing your Berkeley origins proud!
scary conversation
Hey, A. I've mentioned this proof to you before.
04:10
@AlekosRobotis You're Zlatan right
yes @BalarkaSen
Nice. Long time!
Zlatan is the name I have in a discord server I seldom frequent lol
04:11
Discord is very dangerous, I have a lot of friends on there who are quite distracting
@Ted: Yeah I just don't know enough Chern-Weil theory to understand this I think; one day
so I don't really go on it
discord is super addictive its very unhealthy
this chat is also super addictive but i get math done
it's semiproductive to chat about math
how is undergrad going @BalarkaSen
It's just a Bianchi identity proof, keeping track of Lie algebra-valued forms.
04:12
There's a purely probabilistic proof of Chern-Gauss-Bonnet that I would like to eventually understand; the notes I am supposed to read it from is in the back burner
that sounds pretty wild @BalarkaSen
Pig
Pig
are there math channels on discord lol
That's intriguing.
@AlekosRobotis Not bad. Of course, with the pandemic, everything is up in the air
@Pig u dont wanna know
what is the situation like in india? actually I'm doing a DRP with a cornell undergrad who is in india rn, but he doesn't seem to have a good idea for how it is there
Pig
Pig
04:13
:o why
yeah I think basically the idea for surfaces (so just Gauss-Bonnet) is a Brownian motion gets trapped for a long time if a certain part of the manifold is positive curvature, and escapes quickly if a certain part is negative curvature - so you should be able to read off total curvature by running a BM on a surface for a long time
tbh I learned CGB mostly because I think it's a beautiful result lol, I don't think it will be useful for me, but maybe I should learn Atiyah-Singer someday ;)
@AlekosRobotis bad. it just became 4th according to number of cases in the world; it was something like 13th a week ago
complete outbreak
Pig
Pig
hope you are safe man
the whole situation is scary
yup; thanks
it is very scary but this is probably one of the easier things we're gonna face this century
04:17
imagine that
i hope you stay safe, it's a rough time
on the (very light) bright side, the end of history is over
things are happening again
Thanks, you too (u still in NY?)
@Fargle Yes, holy shit
now I'm based in "Ithaca"
which is 4 hours from new york city
ahh. stay safe
also, heya everybody
04:19
it's a bit comical, since it is in no way the objective of the odyssey
hi @Fargle
Can someone please give me a hint to get started with this problem. I have no background at all in proving inequalities.
when in doubt, simplify and expand @AfronPie
Pig
Pig
when in doubt, lower bound x^2 + 1
@Fargle Do you mean multiply those 4 terms? That'll take forever
well, Pig's suggestion also factors into this
you don't need to include all terms---e.g. (p^2 + p + 1)(q^2 + q + 1) >= p^2q^2 + pq + 1 since all terms are positive
04:28
Hi @Fargle
Pig
Pig
this lower bound is too weak
or you can just directly note that p^2 + p + 1 >= p^2 + 1, etc etc
heya @Ted
@Fargle I don't understand the reasoning - just because they are p,q,r,s are positive, why can you not include all the terms?
Ohhh
04:40
Fargle's good :)
if I have seen far, it is because I have rooted for the New York Giants
or something like that
The New York Giants were a long time ago, long before you existed.
Oh, wait, I'm thinking only baseball.
I think NY giants is a football team now? Though I am no authority on US football loll
Yeah, that's why I added my second sentence.
yep
04:48
I abhor football.
not a big fan of it myself; I was just hunting hard for a pun
Where was the pun?
well perhaps "pun" is the wrong word, but the wordplay
concussionball
Where was whatever?
04:50
"if I have seen far, it is because I have stood on the shoulders of giants"
Ah. And your name suggests seeing far.
sigh
how I've missed this chat
Sarcasm duly noted.
nah, I meant it---not often I'm among my people
(dorks)
:)
LOL, silly Fargle.
04:57
are you in quarantine?
self-imposed, more or less
ah I see, yeah it's been a few months now I suppose
not very fun.
good for math
I got stuck again. Is there some kind of thought process I'm supposed to be having for solving the inequality? I got wolframalpha.com/input/?i=%28%28p%5E2*q%5E2%2Bpq%2B1%29%28r%5E2s%5E2%2Brs%2B1%29%29%2Fpqrs%3E%3D81. Also, I see that some of the solutions have for example r<0, so I'm guessing that means that my bound was too weak?
wolframalpha.com/input/?i=%28%28p%5E2*q%5E2%2Bpq%2B1%29%28r%5E2s%5E2%2Brs%2B1%29%29%2Fpqrs%3E%3D81
Pig
Pig
@AfronPie 4 numbers is kind of arbitrary
Pig
Pig
05:10
and your inequality is quite symmetric
what about instead of p,q,r,s - try to formulate the analogous problem for only p,q - can you solve it? If not, can you solve a more simplified version?
Ok @Pig I will try that. Sounds like a good idea
@Pig Also, just making sure based on the picture I posted above
My simplificaiton was too weak, right?
Pig
Pig
uh, i don't know what you are doing
Ok never mind let me try your idea of a simpler case.
Pig
Pig
05:39
?
I think I got it. It ended up being just to prove p+(1/p)>=2. Just to make sure, since the inequality is symmetric, then after I just prove it for p, the others follow by the same argument right?
@Pig Thanks for your help btw. Doing the analogous problem for just p really helped.
Pig
Pig
:)
 
3 hours later…
08:51
I was solving a rigorous problem $(x^2-8x+1)^{x^2+2x+1} =1$
I have no idea how do I solve it, I even I differentiate it but no improvement.
09:17
The Power Looks like a bit of a red herring
I've confused myself about some linear algebra, if I have $\Bbb{R}^2$ with the standard (1,0) and (0,1) orthonormal basis and I use this basis to label vectors by their components, I can label the vector say (2,2) by it's components in this basis. If I then double the length of both basis vectors the components are now (1,1), but these components are relative to the components in the original basis, which I chose arbitrarily and labelled as having unit length?
actually I think I get it
09:38
let's talk about basic group theory
I am sure everyone online right now understands Orders of Products except me.
Guy tell me how do you Find the order of following permutation: (12)(345)
why is it 6?
What does order or permutation even mean.
What does order or permutation even mean?
If you're just after the definitions can't you google them?
I'm not trying to be rude, but it would be easier if you looked them up and asked if you have a specific question about a word or phrase being used than just asking for a blanket definition
@Charlie I know. I forgot to Google one.
All good :)
09:44
I mean sometimes I come here blindly.
@Charlie Seems like you are a Physicist.
Or physics student.
I have problem for you.
I'm actually a chemistry student but I'm trying to become a physicist
oh no
Then I need keep my mouth shut.
I mean I'll try my best but I'm not exactly a high level physicist
if you want to message me that might be better, we don't want to practice the dark arts in the maths chat
Well this problem is for a professional physicist or a very experienced professor in field of physics.
on what topic?
09:50
But I am curious about Chemistry course.
@Charlie Very very board.
I can hardly search any chemistry course in web.
Can you tell me list of textbooks required in undergraduate course of chemistry in your university? Really curious. I hope it's not very outdated.
resources for chemistry are much less available than those of physics
if you want the help of an expert physicist the physics SE is literally full of them
Depends which topics you're interested in
@Charlie yeah the hbar.
yes
what area of chemistry are you interested in?
if you just want introductory stuff you should look for the standard highschool textbooks, if you want undergraduate material you'll have to be more specific than just chemistry
@Charlie I am not really interested in chemistry unlike Mathematics, Physics and philosophy but I'd love to finish undergraduate chemistry since I'd be doomed when I don't understand it well.
chemistry can actually be pretty nasty conceptually
arguably more frustrating to learn than physics or maths since quite a lot of information has to be taken on truth before you can attempt to understand it
09:55
You mean chemistry undergraduate choose specific topic in chemistry to study and those study materials are manually selected?
no as in if you want to learn about a specific area of chemistry I'll recommend you the textbook I used, but that will depend on the topic, you won't learn organic and inorganic chemistry in the same textbook generally for instance
@Charlie That's why I am trying to master undergraduate CS,Physics and Math same time for it.
Just want standard course material list or topic that you study as undergraduate students.
have you done highschool level chemistry?
@Charlie I am instead jumping directly to undergraduate one since I did same for Math and Physics.
then you need to be specific about what area you want to study
10:00
@Charlie Inorganic chemistry.
I learned from weller, overton, rourke, armstrong, inorganic chemistry 6th edition
@Charlie Is that name of a single book?
the authors and the title yes
Sounds like lots of collaboration needs in your field.
it is a very broad field
10:04
Did you learn Chemistry from a single book?
that and my lectures
admittedly most of my learning was done 2 weeks before the exams while on a possibly lethal dose of caffeine
i wasn't a good student
Does lecture include knowledge which are outliers?
I have to head off for a while, have fun learning
no but the lectures tend to be more specific about what they want you to learn than an entire textbook
and it's useful to have something explained in several different sets of words
anyway, see you later, good luck
@Charlie Later :)
Group theory is one of the most aesthetically pleasing subject I have ever intersect with so I will choose number theory as my field to study as an autodidact.
10:13
Just need some tips&tricks from those who study number theory as a graduate student or a professional number theorist to save time learning this topic.
@EdwardEvans Well it is related with abstract algebra but it is also related to number theory.
Might sound odd.
Its just, what you said is like saying "i like cycling so i'm gonna learn to drive a car" or smth
@EdwardEvans Your profile says that you are graduate student who is learning Number theory â—‹_o
Trying to learn number theory
@EdwardEvans Do you have any tips to learn it fast .You may some of it given by your instructor which you can share here.
I found self studying really time consuming.
If i knew how to learn fast i'd have a PhD already lol
10:23
B-P you just assumed your rate of speed. I mean little optimization practically or be more realistic in other words.
Well may be I am putting less constraints.
Just make sure you learn things thoroughly, otherwise youll end up having to go back and learn some basic stuff before you can continue (i am in this position and its a time sink)
Also delete your account on this site, its a massive time waster
3
@EdwardEvans No! It's a good place to be where experts like you can give me tips something more related to experience and also good place to ask dumb question.
I'm glad you think i'm an expert but that is further than far from the truth
i like algebra so im gonna learn higher topos theory
Anyway i'm only joking, i just waste a lot lf time procrastinating be
Here*
@Thorgott haaaa
10:30
@EdwardEvans You are expert as yourself since you have property of being you.
@Thorgott That's a good roast XD.
@EdwardEvans I never thought Math Student have sense of humor so I pretend to talk in a serious manner.
Not gonna waste your time tuss!
10:47
does anyone know a good reference which treats basic rep thy of compacts groups?
I basically have found the results I need, but they're mostly (snippets of) lecture notes
would like to have a proper reference
that looks nice! thanks
11:22
Good night girls!
@Yuvraj actually i was being dumb, you want x for which the expression in parentheses is 1 or for which the exponent is 0
@Yuvraj Take natural log or sink.
You can solve it by inspection
11:30
@Yuvraj Hint:Take natural log.
Why would you even differentiate?
Well I am not expert. I'd better keep my mouth shut.
Good night. I will sleep instead of wasting time here. See you all at morning if I'll be able to survive this night.
Ok I'll be serious.
$\ln(x^2-8x+1)(x^2+2x+1)=0$
well here you go your exponent is slated by me.
You can let one of your multiple get killed by that 0.
$\ln(x^2-8x+1)=0$
or $x^2+2x+1=0$
Why do I feel this problem is a trap to get roasted XD.
I mean I will again get roasted for answering this question lol.
Will I get suspended if I chat like this BTW good night. Hey I challange everyone to flag my chat right now. Lemme see if you can get suspended for just higher flag. I am testing if it is A.I which decides to suspend you or the moderator.
Can anyone tell me how to compile the latex in chat visually or otherwise I feel attacked for answering answers. Just do visual steps for android!
@EdwardEvans Yes you were right that this chat is kind of good procrastinator software.
Doesn't really help
12:07
@EdwardEvans ok...?can you show some steps of your thought
@Questionno.1Iamselftaught no issue!
@Yuvraj sorry for being rude I suffer mental illness called math rage
3 mins ago, by Yuvraj
@Questionno.1Iamselftaught no issue!
I was angry since I lose candy crush lv 199 which was pretty hard and now I got no lives to play.
@Questionno.1Iamselftaught you are always welcome to show your thought on any question
I will always come here if I lose my 5 life in candy crush. But hope I am not in rage mode. Good night.
12:46
Guys Here is one quotes from me:
Don't give up on a dream.
Keep sleeping!
13:22
if you have a distribution of points on a unit disk what are some ways to analyze the pattern of the distribution of points?
maybe a fourier transform on the (aperiodic) point sets?
Hi everyone, maybe I should ask this a question but want to try my chances here, because it's very short, would be really great if someone can say "no everything is correct in the book" or "you're right": In the proof of Prop2.2 in Jardine's Simplicial Homotopy Theory, while trying to prove that the map is a monomorphism, is there an obvious typo? Namely shouldn't we use the inverse of the $\Psi$, especially because we can't know if the "components" of $d^{*}(x_{\sigma})$ are degenerate or not
I am confused by the syntax...
1
Q: What is a fully convolution network?

PyWalker27I was surveying some literature related to Fully Convolutional Networks and came across the following phrase, A fully convolutional network is achieved by replacing the parameter-rich fully connected layers in standard CNN architectures by convolutional layers with $1 \times 1$ kernels. I ...

 
1 hour later…
14:41
I like higher topos theory so I'm gonna learn about mythic spaces
14:54
Hello!
Anyone here knows the "easiest" proof(requiring least pre-requisites)to the theorem that
The number of ways in which an integer can be expressed as sum of square of two integers is 4(d_1(n)-d_3(n))

Please forgive the lack of rigour in the statement,I know only basic number theory.
 
2 hours later…
16:36
0
Q: Ways to analyze this discrete point distribution?

geocalc33I made an aperiodic point set on a disk and wanted to figure what symmetries are present. By inspection it looks like the points have 8-fold rotational symmetry. Someone said there might be some hyperbolic symmetry present. So what is this pattern called and what are the symmetries of the point...

ideas?
 
1 hour later…
18:04
Is there a natural manifold structure on $\mathbb{C}^n/S^n$?
smooth manifold, that is
18:41
@Thorgott what is that expression meant to denote?
I think he meant $S_n$.
And the answer is that it's very special to $\dim\Bbb C = 1$.
This is important in curve/Riemann surface theory.
@TedShifrin In that case I assume it was meant to be $S^1$ and not $S_1$?
No, no. $n$th symmetric product of a curve is a complex manifold.
18:47
But then we have the quotient of a space by an action of the trivial group. That does not sound very exciting
Did you read what I wrote?
I am now realizing that I misunderstood the meaning
LOL, OK.
I thought you meant that it only happened for $n=1$
No, I meant that if you do a higher-dimensional vector space (or complex manifold), the symmetric product is a singular space.
18:50
I think my brain is fried today. I spent most of it manually creating payments in a CRM system because of a software error that had caused the system to not do so itself
I feel fried most of the time in this world.
You would think people would try to pay at most twice when it does not go through but does not give an error. Or at least check if the money is getting transferred from their account.
But there were people who had tried 10 times within 30 minutes
Yeah, I'm stupid like that sometimes.
oh, sorry, I indeed meant $S_n$
symmetric group acting via permutation of coordinates
19:38
it appears I have to figure out whether $\{(x,\sigma x)\colon x\in\mathbb{C}^n,\sigma\in S_n\}$ is a closed submanifold of $\mathbb{C}^n\times\mathbb{C}^n$ to start with
19:52
I think it isn't
Here's another approach: Can you think of what might give you a chart on the quotient?
 
1 hour later…
20:57
I spent 20 minutes finding complicated explanations for what the sheaf $\mathcal{F}^*$ might be, when there was already a sheaf $\mathcal{F}$ floating around. I constructed some exotic explanations before realizing it was just the dual.
oof
Um ... :D
I'll pretend it's the fault of the author (there were a lot of other things going on in that paragraph)
I'm sure the author is incompetent.
when was the last time an American male tennis player won a grand slam?
easy: Andy Roddick
21:11
you're right
just checked
It's Voisin's book on hodge theory. She is obviously brilliant. Some parts of the book are a bit confusing, though. There are a lot of typos, too.
There was a "proof" about the Hodge structure of a blowup, which was incorrect in many ways. (the first line consisted of a mis-indexed long exact sequence of a pair) and it only got worse
Hmm, that's sort of surprising.
I like the book, though. It's concise in a useful way.
@geocalc33
Consider the abelian group of integer functions $f : \Bbb{Z} \to \Bbb{Z}$.
It's also possible that the translation has made the writing less clear
21:18
I never like translations.
21:37
Graph energy is the energy of the matrix representation of the graph, where the energy of a matrix is the sum of singular values of the matrix
qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq
qqqqqqqqqqqqqqqqqqqqqqqqqqqqq
1+2
22:44
Hi, I just stumbled across a post https://math.stackexchange.com/questions/3717380/showing-a-function-f-mathbb-r2-to-mathbb-r2-is-partially-and-totally-diffe

but do not have the rep to point out neither answer uses the function OP mentioned in their post. Could someone comment this on the answers?
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