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00:00
No worries. Take care.
By the way, the integral does seem to evaluate to $1$ (when the $\sqrt{32 \pi} $ in the denominator is taken into account), if you were referring to that.
@Bob
00:32
@MikeM: You make it back at long last? :)
About 18 hours ago
well, thank goodness
Not that I'm looking forward to my 1000+ mile driving expedition ... who knows where there might be fires or breakdowns ...
2
01:21
@Ted where are you heading?
 
1 hour later…
02:49
Anybody from algebraic topology, tell me if this equation about the fundamental group of the circle is accurate, I wanna get it tattoo'd on my forehead: $$\pi_1\partial\mathbb{D}\cong\mathbb{Z}$$
03:17
0
Q: Show that $\int_0^1 4 \space li(x)^3 \space (x-1) \space x^{-3} dx = \zeta(3) $

mickMy mentor tommy1729 wrote $\int_0^1 4 \space li(x)^3 \space (x-1) \space x^{-3} dx = \zeta(3) $ I wanted to prove it thus I looked at some methods for computing integrals and also representations of zeta(3) that might be useful. But nothing was very helpful to me. In particular the fact that t...

Any ideas ?
 
1 hour later…
04:38
@M.Nestor I would say $\pi_1(\partial \Bbb D^2) \cong \Bbb Z$ and advise you to think twice before getting a tattoo since it would last forever (even when you regret it)
 
4 hours later…
08:21
@M.Nestor wut
@M.Nestor maybe you want to tattoo a proof of that as well? I wrote up a really simple and elementary proof here: overleaf.com/read/qvqpmfzjchss#/63957916
2
@MatheinBoulomenos lmao
@MatheinBoulomenos Elementary (+1)
09:08
$$\int_{-1}^{1/2}\dfrac{e^x(2-x^2)}{(1-x)(\sqrt{1-x^2})}dx$$
@LeakyNun Are you there for something else?
@LeakyNun $$\int_0^x t^2 \sin(x-t)dt = x^2$$ , Find number of solutions in $[0,100]$
@MatheinBoulomenos can I share it with my professor lol
09:17
@LeakyNun Adding original equation and its double derivative, I get: $x^2 + 2= 0$
@LeakyNun sure
hence no solution,
hi @Daminark
But thats not the answer given in my book @LeakyNun
Please tell my mistake
@Abcd $x^2 + 1 = 2x^2$ has no solution because taking twice derivative gives $1 = 2$
09:18
@LeakyNun ????
1 min ago, by Abcd
@LeakyNun $$\int_0^x t^2 \sin(x-t)dt = x^2$$ , Find number of solutions in $[0,100]$
@LeakyNun I differentiated this equation^^^
@Abcd T/F: $x^2 + 1 = 2x^2$ has no solution because taking second derivative gives $1 = 2$
@LeakyNun false
I mean, $2 = 4$
09:20
@LeakyNun so basically we cant equate derivatives that way. ok
why not?
@LeakyNun But you only said that it gives 2=4
well 2=4 clearly has no solutions
@LeakyNun but x=1 is a solution
Like after differentating my equation I get:
there's a simpler example: $x=1$ has no solution because taking derivatives gives $1=0$
09:21
so why can't we equate derivatives?
@MatheinBoulomenos so $\pi_1$ of topological group is abelian?
$\int_0^x t^2 \cos(x-t) dt= 2x $
Now differentiate again
$-\int_0^x t^2 sin(x-t)= 2$
@MatheinBoulomenos interesting
Now add initial and final equations
$x^2 + 2 =0$
Why is this method wrong @LeakyNun @MatheinBoulomenos
09:23
because you just said that we can't equate derivatives
2 mins ago, by Leaky Nun
so why can't we equate derivatives?
3 mins ago, by Leaky Nun
why not?
@LeakyNun But why can't we equate derivatives?
@LeakyNun Please reply
0
Q: Show that $\int_0^1 4 \space li(x)^3 \space (x-1) \space x^{-3} dx = \zeta(3) $

mickMy mentor tommy1729 wrote $\int_0^1 4 \space li(x)^3 \space (x-1) \space x^{-3} dx = \zeta(3) $ I wanted to prove it thus I looked at some methods for computing integrals and also representations of zeta(3) that might be useful. But nothing was very helpful to me. In particular the fact that t...

think about two graphs $y = f(x)$ and $y = g(x)$ @Abcd
a solution of $f(x) = g(x)$ is where the two graphs intersect
but the slopes don't have to be equal
 
2 hours later…
11:44
Afternoon all
Hey there
they here
:thonk:
:bonk:
11:45
gwarn
wah gwarn
Got a job carrying out the university's "PC fleet refresh"
yay
coolio
As in, this will be a job you do in grad school? Instead of babysitting undergrads? :P
@Daminark nah this is just for the remainder of the summer, I think I will end up working in a bar or smth for grad school
hahah
11:51
Ah, lmao
is this for mathematics?
I am under the impression that most math PhDs get financial assistance
including TAship
@Iza_lazet I'm doing a master first; maybe you're talking about US grad school?
Fair, here we get some financial assistance for PhDs but for the master you get 10609 pounds, of which i have to spend 7695 for tuition
lol
is that an interest free loan or a scholarship?
12:01
It's not even interest free, but it's not repayable until you start earning over like 21k
and you pay like 6% on everything over 21k I think
12:21
Hey @Mathein and @Loch
hey @Daminark
How's it going?
pretty well thanks
have an ANT exam tomorrow
@Mathein viel glück ;P
Good luck!
12:25
thanks
12:46
taking some time off from math because i'm struggling with some mental health issues :( i'll be okay though bye for a few weeks
Alright, take care of yourself
wonder if anyone who is familiar with graphical models in statistical applications (Bayesian inference) can help me sort something out
 
1 hour later…
13:55
Good morning again everyone: It's probably time for me to mention the 100th ring competition/celebration on my site: https://chat.stackexchange.com/transcript/message/45549614#45549614

If you'd like to have your handle enshrined with your winning ring, please take a look a the guidelines and I hope to see your suggestion soon :)
@AlessandroCodenotti Are you disappointed or are you cosatisfied?
lol
Hi @rschwieb
morning
I'm looking at the inspiration page of your website, isn't it very easy to construct a quadratically closed but not algebraically closed field?
14:11
I see you also need an ordered but not archimedean field, such an order can be defined on $\Bbb Q(x)$ if you already have this field in your database
14:28
@AlessandroCodenotti . Yes, it is: i believe there's a suggestion in the queue to fill that gap, but those aren't being processed until August 2 :)
@AlessandroCodenotti There are some easy ones yes: the issue is that there are so many easy things to do that I don't have the ability to find and do them all myself.
@AlessandroCodenotti And there is a small bit of nonsense on the inspiration page too: please check out the FAQs for a description
@AlessandroCodenotti Your comment on $\mathbb Q(x)$ would make a great suggestion submission. Please describe the order and anything else that might be useful for me to know :)
0
Q: Asymptotics to $f(n) = \int_0^1 ( \frac{li(x)}{x} )^{2n + 1} \space(x-1) \space dx $

mickConsider $$f(n) = \int_0^1 ( \frac{li(x)}{x} )^{2n + 1} \space(x-1) \space dx $$ Where $n$ is a positive integer. ( I know that $f(1) = \zeta(3) $ but I already made a Question about proving that ) If I am not mistaken $f(6) = 123 482 $ or about that value. ( I assume not exactly that integ...

Snapshots of Mathematics
in Sub-Saharan Africa
14:50
Hi @Daminark
What's up?
We start by defining the order on $\Bbb Q[x]$ and we basically use the antilexicographic order, let's say we have two polynomials $f(x)=\sum a_ix^i$ and $g(x)=\sum b_jx^j$, we let $k=\max\{n\mid a_n\neq b_n\}$ and we say that $f<g$ iff $a_k<b_k$
Also this
2
Q: Show that $\int_0^1 4 \space li(x)^3 \space (x-1) \space x^{-3} dx = \zeta(3) $

mickMy mentor tommy1729 wrote $\int_0^1 4 \space li(x)^3 \space (x-1) \space x^{-3} dx = \zeta(3) $ I wanted to prove it thus I looked at some methods for computing integrals and also representations of zeta(3) that might be useful. But nothing was very helpful to me. In particular the fact that t...

nothing much - was just replying to your 'hey' earlier :)
This is not archimedean because $x$ is bigger than all naturals and it's a bit of a pain to check but under this order we actually have an ordered integral domain
This order can be extended to an order on $\Bbb Q(x)$ in the same way the order on $\Bbb Z$ is extended to $\Bbb Q$ @rschwieb
14:53
Oh I know, I just meant it in the greeting/how's it going? sense :P
The clip on my left shoe is stuck, I resign myself to a life of left-foot-imprisonment
@loch Hey . This is a reply to your reply on 'hey'-ing @Daminark. Give me a hey once in a while, why don't ya xP
hey @Nick
15:09
Nickelodeon
 
1 hour later…
16:09
Hi all!
hi @Rudi_Birnbaum
Hoi @Rudi
@MatheinBoulomenos: When is your exam in mod forms? ; Servus @ÍgjøgnumMeg!
it was last week
I had some line of thoughts with came to an unexpected end. It starts with the "idea" that primes might be exactly at the border between "regular" and "random". So lets suppose you have some parametrized equation which has either "regular" solutions or when you vary the paramater it can give you some "random number"-like solution. This is not completely crazy.
@MatheinBoulomenos: Hope it went well!!
Since in Physics its known that when you have a flow and you vary a certain parameter (the Reynolds number) the flow changes from laminar to turbulent (which has certain properties of randomly distributed).
16:18
@Rudi_Birnbaum ich hab eine 1,0 :)
Now I asked myself how such a flow is discribed mathematically. And that os now the surprise (for me): Its Navier-Stokes, thus another Milennium problem.
@MatheinBoulomenos: Hej, super!!! Glückwunsch!!!
@Mathein sagt man in Deutschland "die" 1,0 oder wie?
aber hey nice! lol
hab ich nicht gewusst
Gratulieeere
@ÍgjøgnumMeg: ned überall wir sagen auch "einen Einser".
16:19
ah okey :)
@Rudi Isn't your idea basically the reason why random matrix theory is a possible approach to the RH?
So it was a bit of a surprise that the one Millennium Problem (explicit formula for primes => RH) leads to the other one.
I don't know about the basic idea of the random matrix theory.
I just know the observation on the eigenvalues.
I mean, having a line in the complex plane along which you have an infinitude of poles isn't really to the zeta function
@Semiclassical are you missing the word "unique"?
Also hey
poles or zeros?
woops
yes
poles
you also see it when doing the contour integral for the gamma function iirc
and it gives rise to some pretty weird asymptotics
(that's more broadly an example of Stokes phenomenon, which is confusing)
16:24
No it isnt, you are right. My idea was just to look at any systems "bearing" a continuous connection between random and non-random.
Fair, I like the analogy with laminar and turbulent flow
Then the other one would be the famous Bender ... Miller Hamiltonian.
Yeah
I know about the gamma function stuff in part because of stuff Berry wrote, btw
So it might be that any such system is potentially very interesting. But then it seems no one is really completely understood. And here we are again with our Milennium problems...
and he's another person who has played a role in the whole RH - QM comparison
16:28
Hello everyone! Is there any ratio in which the orthocentre divides a perpendicular of any triangle drawn from vertex to opposite side?
Its also pretty much in line with Freeman Dyson about the quasi crystals. Though it seems he introduces a second parameter dimension to the problem. His quasi-crystals might correspond to entities exactly at the border between random and non-random. In a way connecting all the problems with continuously connected random-non-random solutions
To build a theory for such systems it seems one needs a complete understanding of the meaning of "random", which as far as i know is also kind of an open question.
16:54
Terry Tao also got an example from Physics. Phase transitions. The solid state corresponds to a complete order (periodicty) and the liquid (or gaseous) state is randomness. terrytao.wordpress.com/2018/01/19/…
Its not the correct link, I am searching for the correct one ...
17:11
"I have a sort of statistical mechanics intuition for the zeroes of H_t which may help clarify the situation. A bit like the three classical states of matter, the zeroes of H_t seem to take one of three forms: “gaseous”, in which the zeroes are complex, “liquid”, in which the zeroes are real but not evenly spaced, and “solid” in which the zeroes are real and evenly spaced. ...
I'll note that one big idea you see associated with phase transitions in physics is that of Lee Yang zeros
the idea is that, if you've got a finite system, then when you compute the partition function you'll end up with some polynomial function of the system parameters
and as such you'll have zeros
what's neat is that, as you go to the thermodynamic limit, these zeros may accumulate along some line in the phase space. in the thermodynamic limit, these becomes lines along which the partition function changes non-analytically
and that's a phase transition
18:15
$$\operatorname{Gal}(L/K)^{ab} \cong C(K) / N_{L/K} (C(L))$$
18:41
@Semiclassical interesting!
yeah
not something I'm a huge expert in, mind
@Semiclassical interesting!
@Semiclassical: One question is $\beta$ (what I would call the temperature) here $\in \Bbb C$?
actually, that's reciprocal temperature $\beta = 1/k_B T$
(actually, it's really reciprocal energy but no one calls it that)
usually we only talk physically about $\beta>0$
oh yes sure,
(you occasionally see $\beta<0$, actually, due to the possibility of negative thermodynamic temperature)
18:52
but does "analytic" here imply complex as well?
which would be strange...
however, it's still useful to look at complex $\beta$. the reason is: If you have lee yang zeros coalescing along an arc which crosses the real line, then in the thermodynamic limit you end up with a phase transition there
also, note that zeros in complex beta i.e. complex temperature would correspond to an imaginary temperature
which suggests that there's some linkage to time-dependent phenomoena through the whole temperature <-> imaginary time connection you see in field theory
so it wouldn't surprise me if, at least in some theories, zeros in complex $\beta$ would correspond to a state with energy Re(beta) and energy width Im(beta)
sooomething like that
OK! I don't recall/understand where the equation for $Z_G(T,V,\mu)$ comes from.
the polynomial one in $e^{\beta\mu}$
it's standard stat mech stuff
that's how the canonical partition function comes up
18:58
Hmm yeah somewhere in the back of my mind ...
oh, the fugacity one
that's just the fact that the Gibbs free energy includes a term $N \mu$
where $\mu$ is the chemical potential
which means if you go from the canonical ensemble to the grand canonical ensemble, you end up including a factor $e^{n \mu /k T}$ for the n-particle state
Oh yes!
thanks
it's how you accomodate the fact that particles should be able to leave/enter the system and the equilibrium condition for that
I should also point out these paragraphs, though: math.ucla.edu/~biskup/Summary/PFzeros.html
in particular: "However, despite the beauty and conceptual appeal of this theory, the problem of finding partition function zeros explicitly has proved to be so intractable that Lee-Yang program has failed to be implemented in any practical study of phase transitions."
so there's some interesting theory stuff going on, but it's pretty removed from actual model-building
Hm yeah, its "physics like".
19:31
Prime numbers again
I'm taken aback but how much better Munkres is than the other topology books I've been attempting to use
I've read only small sections of it but Munkres is the standard suggestion for a topology book
@Alessandro the explanations are vastly better than other books I've seen so far
lol
@ÍgjøgnumMeg Yeah, Munkres was a very helpful book
I like Hatcher's brief notes on point set topology
beautiful
You don't need much input to do algebraic topology which is what most people are prepping for
@Mike I am basically just prepping for topological concepts in other fields, rather than for the study of topology proper
@LeakyNun nice! I was wondering for a long time about these!!
19:52
lol
Fields like what?
@Mike algebraic number theory and geometry mostly
I feel like you need vanishingly little topology for that tbh, some definitions...
Exactly! lol
but I guess it's probably something that I should have under my belt for future reference
I'm taking a module on complex analysis and eventually modular forms in my master so I feel like I should know some stuff
but in my ignorance I don't know whether or not that's true
Certainly never any harm in knowing more stuff
You probably never need any of the meatier stuff later in the book, esp say metrization theorems
19:59
@ÍgjøgnumMeg have you got any lectures from I.F.?
Right, I'm kinda going through the basic definitions and stuff; standard topologies (subspace, product, quotient), bases, compactness/continuity, Hausdorffness
@Rudi Yeah Algebraic number theory is given by him
Is he a good lecturer in your op?
@Rudi I haven't started yet so I don't know! But I'll report back once I've had a class by him ;)
:-)
I would die for his take on Stix-Scholze critics ...
Maybe I'll ask him to supervise my master thesis and then you can just send me questions ;)
hahaha
20:03
:))
Ahhh, I actually applied to study in Frankfurt where Stix was teaching lol
and Alessandro is studying in Bonn but I don't know if Scholze teaches
@ÍgjøgnumMeg after all I like his (IF) web page and his collection of maths jokes. I wouldn't be too surprised if Scholze is not a perfect lecturer at the moment. I saw his inauguration lecture and you could see how is not too experienced yet. Though I guess he would be a hell of a great supervisor in research ...
@Rudi His inauguration lecture was about the analogy between covering spaces and galois theory right? I think I saw that
@ÍgjøgnumMeg Yes, its on youtube (where I saw it).
Right, I saw that
I was pleasently surprised by how easy it was to understand (I have no education in German mathematical vocabulary)
pleasantly*
idk
20:10
@ÍgjøgnumMeg I cannot say anything on the contents and I also felt he was explaining things well, but I noticed he was not completely "souverän" in his style (which anyway might not be a big thing), but still was noticeable. I have no problem with it, hes a genius (as they say) and very young. And with both things come pros and cons.
@Rudi right, I think he seemed nervous in some way
but anyway he apparently teaches alg. geo. at Bonn
@ÍgjøgnumMeg yes a bit. I suppose he will quickly get a very good lecturerer if he puts in a little effort. I read lots of Maths in German and I like it. In my subject (Chemistry) O do almost everything in English (including the masters lectures) and its fine. But in Maths I appreciate German. Also when you read historical stuff, löike Gauss or Klein, its cool and I think a priviledge to be able reading it in original.
@Rudi Fair, I shall probably expand my maths German over the years
it's not too hard tbh, it's harder to write it because I don't know the stylised "lingo"
I see. We have a high-impact journal "Angewandte Chemie" and they have a German and an International version. When a paper gets accepted they offer that you can translate it on your own and you get some 100 Euros. I noticed its harder translating a German MS into English than writing the MS in English and translate it to German. You start noticing that you miss terms and exprssions, what you call "lingo" maybe.
@ÍgjøgnumMeg I know a student who took a class from him a couple of years ago, she said he is a very good teacher, I don't know if he's teaching at the moment though
20:23
@Alessandro Nice! According to his website he was teaching on algebraic geometry in the sommersemester last year
My friend took algebraic geometry actually with him as professor
@Alessandro that's cool, it's not always the case that big researchers are good teachers I guess so maybe your friend was lucky
@AlessandroCodenotti How does it work when you want to study maths in Bonn, is it that you just inscribe and start or is there any selection process?
I don't think I'll do algebraic geometry though
How come?!
20:27
@Rudi_Birnbaum There is an admission process for the master, no idea about the bachelor
@AlessandroCodenotti How does that admission process work?
@ÍgjøgnumMeg Their courses are divided into areas by theme, my main one will be "Algebra, geometry and number theory", which includes all of the logic and set theory course I want to take as well as algebraic geometry, I have to see whether there'll be credits left for it
@Rudi_Birnbaum You need a letter of recommendation written by a professor at your uni, a statement of purpose written by yourself, a transcript of your grades and some proof of your English proficiency
And some more paperwork if you're not an EU citizen I think but I'm not sure
@Alessandro that's fair, I'm struggling to choose between Galois Theory (which I guess will be a refresher) or a course on Elliptic Curves (which will be COOL)
@Alessandro Also when you did your bachelor there?
If the Galois theory course is a refresher you can skip it most likely
@Rudi_Birnbaum I just finished my bachelor, but I did it in Trento, in Italy
20:32
@Alessandro I already have some Galois theory mostly from my study of ANT but haven't ever taken a full course on it so it might be more useful to take that lol, but of course elliptic curves would be really interesting; I might try to attend both and only be examined in one
OK, how many of your commiltons are Bonn bachelors? Any guess?
@AlessandroCodenotti What is take on wine from Bonn area? lol!
No idea, I'll begin my master in October, I've never even been to Bonn right now!
Ah OK! Then all the best for you :-)!!
((Its actually a very nice region, my parents in law lived there for 10 years and I liked it a lot))
(((its within what I call the "habitable zone in Germany")))
@Rudi_Birnbaum lol I wonder how big is that zone
@ÍgjøgnumMeg See if there's a syllabus available and how much of the topics covered you're already familiar with
@Allessandro its not connected. It extends from the south to about the river Danube - actually not really that far, but almost. And then it includes some disconnected areas like Tübingen and sourroundings, Bonn, Köln (to some extent) and the Saarland. And thats about it (maybe the northern most parts close to Denmark). Thats also about my search area for positions in Germany.
20:42
Where are you from if you don't mind me asking?
@Alessandro it basically says "the fundamental theorem of Galois theory lies at the heart of the course" which basically means the Galois correspondence is the punchline of the course, but it also says cyclotomic fields are studied in detail lol
@ÍgjøgnumMeg You probably know way more about cyclotomic fields from ANT than what can fit inside an intro to Galois theory course imho
@AlessandroCodenotti: I was born here en.wikipedia.org/wiki/Rosenheim and studied at the TU-München.
And at the moment I live and work in Salzburg/Austria.
@Rudi jealous!
@ÍgjøgnumMeg about what :D
?
20:45
@Rudi where you live! lol
I very much miss Austria
@Rudi_Birnbaum I see
@ÍgjøgnumMeg Salzburg is a very good place to live( though if I could choose I would prefer Vorarlberg) but for science it has its "limitations"...
@Rudi The only place in Vorarlberg is the FH Dornbirn
Else I would've stayed haha
@ÍgjøgnumMeg yes scientifically Vorarlberg is limited, I guess :D
As is Rosenheim
and to get a proper position in München is extremely hard ....
@ÍgjøgnumMeg you mostly miss the Fleischkäsebrötchen, I know it!
20:50
@Mathein Hahaha, no actually the Leberkässemmel
;)
that's isomorphic to Fleischkäsebrötchen
Dont they call it in Ulm LKW?
@ÍgjøgnumMeg do you have Döner in UK?
@Mathein yes but it tastes like you'll get a terminal illness if you eat it
20:51
Kebap (in Austria)
It's genuinely vile here :(
and it's called a Donner kebab here
because ö is too hard to pronounce apparently
so
we have thunder kebabs
:) yes!!
So is the cantine in Nottingham "recommendable"?
No idea, I, like Alessandro, have yet to visit the city where I plan to spend the next 1-5 years
hahaha
20:53
@Rudi_Birnbaum interesting theory about "habitable zone in Germany"
@MatheinBoulomenos its not completely serious but has some truth ... ;-)
I haven't seen that much of Germany but I really love Heidelberg (and Munich is quite nice, too, I have a lot of family there)
I guess I could extend it by Heidelberg, but I have never been there (for some strange reason) ...
it's a really lovely city
it's kinda small for having such a big university
I imagine it grossly a bit similar to Tübingen?
20:55
(which I actually prefer)
never been to Tübingen, but I heard that yeah
are student flats affordable there?
@Rudi_Birnbaum your birth place looks stunning!
@Rudi_Birnbaum let me phrase it that way: Heideberg is so beautiful that a lot of people want to live there, which has some consequences
@Symposium thanks its really a very nice place. And most of all I enjoy peoples temper there. @MatheinBoulomenos I see ..
but student dorms are affordable
20:58
@ÍgjøgnumMeg I had some yesterday in Shoreditch. I was really hungry, and the first place I saw was a kebab shop. To say it was disgusting is an understatement.
@Mathein I think there actually is a seminar in IUT in nottingham lol
and you can get lucky (like me)
@ÍgjøgnumMeg you can attend
@Symposium wow what have they done to this delicious food
@Symposium when I moved back to England I decided I'd try and get a Döner kebab and it was horrid
kebab in Germany tastes really good
@Mathein I'll just cry the whole time
20:59
It tasted like they cloned something that died and killed it again.

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