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18:00
Maybe a separation axiom?
brb shower
but that's no good if $A$ has bad separation properties :/
There doesn't exist a separation of A if A is the point set
Right, so that's an indication that it might work. But useless formally, since $A$ has to have at least two points
by fiat
Yes we cannot say anything if A has two points.. there can or cannot exist a separation
Since we don't have a correct description of A
18:04
Wait hold on this is ridiculous, wait
the one-point space has no quotients except the one point space
Hello@MikeMiller
that's it that's the proof
given $A$, let $X=\{*\}$.
But cant we easily construct a quotient map from any set to just a point...
Can we do this for something else that is my question
No, you misread what I wrote
If $A$ is a candidate space, which might have the property you're thinking of
then consider all functions $f:\{*\}\to A$.
None of them are a quotient map, unless $A=\{*\}$.
because quotient maps must be surjective.
So there exists a topological space which does not have $A$ as a quotient.
I am saying let $A=\{*\}$ and any given X i can always find a quotient map $f:X\to A$
18:09
Right, we agree on this
And X is not the point set
(X could be the point set though)
@Rememberme: There is no space $X$ other than the point for which every space $Y$ has a quotient homeomorphic to $X$. Even if you throw out special $eY$ you will get no interesting $X$. You might be interested to know that any compact, connected, locally connected metric space can be described as a quotient of $[0,1]$.
(trivial quotient still a quotient)
This is the Hahn-Mazurkiewicz theorem.
18:12
Why only $[0,1]$ @Mike
Well presumably it can also be done with others, but it can, in particular, be done with $[0,1]$.
I never said only $[0,1]$. You can describe $[0,1]$ as the quotient of a lot of spaces $X$, so compact connected locally connected metric spaces are automatically quotients of $X$. $[0,1]$ is just a nice space to work with.
(In particular $[0,1]$ is a quotient of the Cantor set, so you can describe all those spaces as quotients of the Cantor set.)
I think you get better with the Cantor set. IIRC every compact metric space is a quotient of the Cantor set.
@MikeMiller How would you construct that quotient?
18:15
@Fargle: $\sum 2a_k/3^k \mapsto \sum a_k/2^k$.
Ahhh, that makes sense.
@MikeMiller whats $k$ over there
Index of summation
$k \in \Bbb N$, I would assume, @Rem
anyone cares asking why's @Mike ignoring me? perhaps knowing the reason would help me correcting whatever I did.
18:18
@Fargle That is what I wanted
@Mike: Balarka doesn't know why you have put him on ignore.
@Balarka: You seriously annoyed me a couple weeks ago. I don't remember why anymore so I'm unignoring you. On the other hand I didn't have an aneurysm the past two weeks...
lmao
I? Annoyed? wonders when he did that
You guys sound like BFFLs
18:21
Now you're giving me an aneurysm, eyebrows.
Except getting you to look at my trivial observations on galois theory, I don't think I've ever annoyed you for the past few weeks.
Why can't weeee be friiiends?
I don't think we've actually even talked for the past few weeks : I haven't done any topology.
oh, if this is sounding like I'm complaining : I'm not. I just don't recall what I did :/
Well, I haven't seen what you've been saying for the past few weeks, so you haven't had the ability to ;)
Me neither, which is why I undid it.
18:24
probably you don't recall because i didn't do anything at all? :P
Nah, I lost my keys yesterday and my phone and wallet a few weeks before that. I'm just forgetful.
I guess it's good not to hold grudges
@MikeMiller yikes, not good.
I find myself forgetting lots of things that aren't facts or proofs/theorems. I can spout off the Heegner numbers but I can't tell you what I had for breakfast two days ago.
I don't think I had breakfast, but I can't say for sure.
18:26
lol
It's like I'm hardwired to be completely inept at real life, but good at knowing useless things. I'm the perfect trivia bowl partner.
It might not be a bad idea to lock yourself in an office and just get amazon to delivery all your life's needs.
Once I have an office, sure. But I don't matter that much yet.
hmm, I'm not sure if I should start on my galois theory thing. would I end up getting ignored again if I do that?
No, but I probably won't listen.
18:32
ok. just to let you know, I have found an analog for points, fibers over a point in a field extension, an analog for nbhds. hunting for a formal evenly covered nbhd defn of separable extensions right now
0
Q: Computing a double gamma-digamma-trigamma series

Chris's sis the artistWhat are your thoughts on this series? $$\sum _{k=1}^{\infty } \sum _{n=1}^{\infty } \frac{\Gamma (k)^2 \Gamma (n) }{\Gamma (2 k+n)}((\psi ^{(0)}(n)-\psi ^{(0)}(2 k+n)) (\psi ^{(0)}(k)-\psi ^{(0)}(2 k+n))-\psi ^{(1)}(2 k+n))$$ No need for partial/full solutions, but just some thoughts of yours....

You seem to have found an audience in the homotopy theory chatroom, who are probably more receptive than I.
I only hope so.
18:44
@Balarka Any convex subspace of a linear continuum is connected right?
I'm not Balarka, but yes, assuming you're using the order topology on the linear continuum, of course.
Yes the order topology @Fargle
@robjohn@Chris'ssistheartist did you see this one : math.stackexchange.com/questions/527438/…
@Hippalectryon oraux ?
19:00
@Gato physique 1 et chimie
@Hippalectryon ça été ?
@Gato :( j'ai encore fait des erreurs bêtes.
Re-bonsoir
@Hippalectryon au moins tu seras prêt pour l'année pro
Bonsoir @iluso
@Gato Oui c'est vrai.
19:18
@Hippalectryon tu connais bien maple ?
@Gato Pas du tout, on est passé au Python
et c'est bien ?
Python c'est assez bien
"9 comments" "no comments yet" :(
19:28
@EricStucky There might be an approval system...
yeah I was just sad because I wanted to read the comments XD
19:44
@Hippalectryon et ça permet de faire quoi ?
@Gato C'est un language utilisé au delà des maths. Tu as toutes les fonctionalités d'un language normal (C, Java, ...) + des libraries de calcul formel (SAGE)
20:03
les matheux ont peur de la chimie non ? :P
I spent hours trying to make structural formulas in LaTeX for my chemistry lab reports
So annoying
@morphic That's the worst idea q_q
Never build molecules with LaTeX, it's horrible
Hopefuly one day someone will make a module to convert .mrv (etc) to LaTeX molecules
I should have just generated images online and put them in the document
Yeah, it's way easier.
@Hippalectryon désolé, je mangeais, et tu conseilles de l'apprendre comment ?
20:14
@Gato Tu a l'intention de l'apprendre en tant que language de programmation, ou spécifiquement pour des appliquation mathématiques ?
@Hippalectryon chimie orga ?
@Gato at the moment I'm deeply involved in my research. I'll look at it later.
@Gato Oui c'était le 1er exercice de mon oral
@Hippalectryon ça dépend, tu conseilles ?
@Hippalectryon j'aime pas la chimie
:p
@Gato Je conseille de l'apprendre comme un language de programmation, car il est largement utilisé. J'ai même fait un programme rapidement pour aider Owatch il y a à peu près une semaine qui permet de simuler des planètes dans l'espace :D
20:16
@Hippalectryon stylé :)
@Hippalectryon bha je vais faire ça, et tu aurais un bon "cours" là dessus ?
@Chris'ssistheartist no problem :)
@Gato Le tutoriel "officiel" est très bien documenté sinon docs.python.org/3.5/tutorial
@Gato In the meantime you might like this one math.stackexchange.com/questions/1362440/…. Maybe you employ some complex stuff and you're done immediately. ;)
@Hippalectryon merci
Salut @Gato, @Hippa
20:21
@Chris'ssistheartist not sure, I am not familiar with gamma-digamma-trigamma ^^
@TedShifrin Salutations
@TedShifrin Salut, ça va ?
@Gato You can get familiar to it now. :D
@iluso je vais regarder aussi, alors, merci.
@Chris'ssistheartist well, I prefer to start python :p
@morphic: Most of the graphics I import to LaTeX I do in Mathematica or Adobe Illustrator.
20:22
+1 anyway ;)
@Gato Thanks :D
@iluso tu es français ?
@Gato Oui
Il n'y a que des français ici
20:23
@Gato @iluso Avec LeGrandDODOM on va bientôt pouvoir conquérir ce chat :D
@TedShifrin I was writing up my final chaotic dynamical systems project, and I used TiKz to draw the phase diagrams and stuff
I don't know that, either, morphic
I didn't know you could draw stuff in Mathematica
Too bad our school doesn't give free licenses to students
Well, Mathematica draws stuff :)
@TedShifrin c'est notre normandie ici :p
20:24
Évidemment, @Gato.
@Hippalectryon et ton frère
@Gato The way to success in mathematics is not that easy, and it depends on how we define it. In my case, the success in the area I like is producing stuff like Ramanujan, not for the sake of producing such similarity, no, but it should happen naturally. It's about the profound views he had on the stuff and that one can easily figure out reading his notebooks.
Makes a great Tarte à la Normande, @Hippa :)
@TedShifrin Did you draw the pictures in your books with Mathematica/Adobe Illustrator?
20:25
Yes, @morphic ...
@Hippalectryon Miam
@TedShifrin My cooking skills are only rivaled by my knowledge of ancient Greek :(
Yes, @Hippa, I know you're incompetent :P
20:26
Don't take mr eyeglasses' name in vain!
@Balarka says "Everything excluding math is useless" and yet he thinks he might not study mathematics? What lunacy.
I'm running out of stuff to organize, label, throw out ... impatient
Nah you still have to throw me out
Trop lourd pour moi.
@Chris'ssistheartist sure, but to find what is "naturally" (in mathematics) for us is a bit tedious, I am not sure I will be good at it, I like it but it's not my natural attraction.
20:30
@Ted: Then just have a drink.
How not to love such series? :D $$\sum _{k=1}^{\infty } \sum _{n=1}^{\infty } \frac{\Gamma (k)^2 \Gamma (n) }{\Gamma (2 k+n)}((\psi ^{(0)}(n)-\psi ^{(0)}(2 k+n)) (\psi ^{(0)}(k)-\psi ^{(0)}(2 k+n))-\psi ^{(1)}(2 k+n))$$ It's brilliant and full of meaning in every way.
@Chris'ssistheartist I said I like mathematics, not sure about the converse..
@Chris'ssistheartist Most people won't see any meaning there. Just as most people won't see a meaning in calculating more decimals of Pi
Ah, there's the professional thing-loser :) All organized now, @MikeM?
20:31
No.
@Hippalectryon Well, I don't
@Hippalectryon Indeed, just as certain people have no interest in the mathematics I love.
Are sais related to the letter psi because the weapon sai looks like the letter psi
@Hippalectryon It depends on how you look at this series, because when I look at it a see a lot of marvellous connections with other fantastic results.
Oh oh @MikeM ... didn't make copies yet?
20:32
@TedShifrin Diff Geo ?
And complex algebraic geometry (some very classical stuff), @Hippa.
Oh btw Ted you know lorentzian geometry don't you ?
Not much, @Hippa.
Ah ok :(
@Gato @Hippalectryon Isn't the beauty of mathematics produced by the mathematical connections finally? For instance, you wanna calculate a series or an integral and all you need to do is to be able to make those connections that together make up the marvellous picture of mathematical beauty.
20:34
@Ted: I'm trying to unpack today. Apparently my modem was shipped to UCLA so I'm trying to figure out where it is now, too...
@Chris'ssistheartist Everyone seems mathematics as they want :-) pretty much like art I guess
Oh, presumably in the mailroom? You need to do that key stuff and give the landlord back his spare, @MikeM, before you lose it too.
@Hippalectryon Art, indeed.
@TedShifrin: Mailroom hasn't emailed me that it's there yet.
Sometimes shipping to universities takes days extra, to get through all the layers of delivery.
20:38
@Hippalectryon Mathematics is also about very much courage, trying to do things that no one tried before, no one dared to do before, dreaming and reaching what most of us consider to be impossible.
Btw does anyone here use some ebook reader(-like ) hardware to view maths ebooks ? Any recommandations ? I can't always carry my computer with me :(
@Chris'ssistheartist Isn't that the same for all academic fields ?
You mean your computer that's on fire? @Hippa
Yes, @Ted, and I signed up for time warner the day I should have gotten the modem, and I only got one. They screw with your service if you don't have it set up within 2 days of signing up. Call me the fool, sure, but still.
@iluso Yes, I think it should be like that. I just exposed the view of a self-educated in mathematics, that's me. Some might not agree though, but it's OK.
20:39
@TedShifrin I mean it's heavy and has a wide screen ಠ_ಠ
Oh, weird that that modem would go to UCLA. ... I'm having my own hassles regarding cable/internet. My landlord doesn't have the time to call them up to terminate his service so I can call and start mine :(
ಠ_ಠ
@MikeMiller Don't TW and Comcast have a pretty bad (awful) reputation ?
@Hippalectryon I got a Kindle (the one that displays color) for my textbooks
@morphic Which one ? There are a bunch of different ones (even with colors I suppose)
20:41
@Hippa: All cable companies have an awful reputation. To me, Charter has been the worst. We'll see about Cox, if I ever get it.
@Hippalectryon Kindle Fire HDX 8.9"
@TedShifrin Isn't Google Fiber ok ?
@Hippalectryon: Yes, and just like Edison is a poorly reviewed electric company, I don't have a choice.
But Google Fiber is only in a tiny handful of cities, @Hippa.
20:42
@morphic Wow that looks like a mini iPad :D
@TedShifrin I am willing to study math. Just might not get the chance, as I am likely to fail in my high school graduation.
@Hippalectryon I've held an iPad before but not sure which generation...iPad feels super heavy compared to my Kindle
Pretty expensive though :( (maybe that's the standard price but i'm poor ಠ.ಠ )
@Hippalectryon Yea because it has other applications besides eBooks, but I wanted a color screen for my textbooks with color
That's absurd, @Balarka. You have it well within your control to excel in high school. Now do it.
20:44
@BalarkaSen I'm almost graduating college and you know way more math than I do..of course you can do it
Anyone uses a real reader ?
@morphic: He's far less motivated to study/excel in other subjects.
Not I, @Hippa.
I am trying my best to pass off as an ok-student. Not sure about excelling.
I didn't care much for my gen. ed. subjects either but I guess since our school is easy everyone can get A+ with minimal effort
@Hippalectryon I couldn't find a pure eReader with color support so I just went for the cheapest one that had color
@morphic Is it good as a tablet ? How does it perform compared to others ?
20:46
@morphic In this part of the word, "minimal effort" = "memorizing dis, dis and dis"
@Hippalectryon I'm not sure, I haven't used it for anything other than my textbooks before lol
Most of my high school history was like that, @Balarka, and I too hated that. But I made sure to get a decent grade.
@BalarkaSen Yea...I just memorized everything and got through
If I develop, say, a theory on a mathematical basis of Darwinism by inspection of random walks in the Euclidean space, that's not really considered to be much of an achievement. It's silly, that they want us to learn Darwinism but not understand it.
That applies to everything else, actually.
That's sad
20:50
I had a few good English teachers in high school, one superb science teacher, one excellent French teacher, and one excellent history teacher. The math teachers were mostly mediocre.
We have a good math teacher. The guy who teaches us is a differential topologist, in fact :P
I survived fine, as did many of my good friends. The less motivated and/or less talented students perhaps weren't so lucky.
My geometry teacher had a PhD in math but had a horrible attitude. She punished me for asking questions out of genuine interest. My teacher who taught calculus didn't know it. I resigned from the class and taught it to myself and two friends.
How does a differential topologist end up teaching high school? @Balarka
And why has he not influenced you? :D
It seems to be common that high school math teachers don't know anything more than, at best, multivariable calculus and linear algebra. It's hard to inspire joy when you only understand the bare minimum of inspiration yourself.
Well, to get certified, they are required to have a course in abstract algebra as well, @MikeM, and one in geometry (for teachers). But the average such student is mediocre.
@TedShifrin I don't know the answer to that. He seems to know his topology, though. Got frequent helps from it while learning point-set.
20:53
That's awesome, @Balarka. Where did he go to school? What level did he finish?
Answer to the first question is probably IIT. He's a PhD.
@MikeM: I am not stupid. I've figured out that you've ignored my advice not twice, but thrice. I shall tender you no sympathy in the future ... !
Wow, a Ph.D. Do lots of math PhD's end up teaching high school? Because they want to? Because they can't get a university post or don't want one?
No idea. We have quite a bit of PhD's in our school. The chemistry teacher is awesome, for one, and the history one talks too much but seems to know a great deal.
@TedShifrin I had one with a PhD too
@TedShifrin: I'm going to campus at 3, when the mail room opens. The locksmith is on the way. It's generally fair to assume I've planned things.
20:56
Well, in this country, one doesn't have to be that incredibly gifted or interested to get a Ph.D. But very few end up teaching high school. Those people generally truly love teaching, which is NOT true of most Ph.D.'s here.
OK, @MikeM, I apologize. Locksmith on his way? I've always taken keys to a hardware store or Lowe's or something.
@Ted: Locksmith is on the way to the bus stop, I mean.
OHHHHH.
The comments here are absurd. This is a trivially googleable problem.
You manage to make the English language particularly ambiguous. That's a useful skill :D
It's only googleable if you know what to google. Even I don't know such things. But I'm surprised he'd be working on what he's working on and not have encountered Sard.
Where is @robjohn? It seems he's missing ...

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