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5:01 PM
@Chris'ssis It turns out, the latter integral problem by VR has no closed-form. I'm very disappointed.
13
Q: A couple of definite integrals related to Stieltjes constants

Vladimir ReshetnikovIn a (great) paper "A theorem for the closed-form evaluation of the first generalized Stieltjes constant at rational arguments and some related summations" by Iaroslav V. Blagouchine, the following integral representation of the first Stieltjes constant $\gamma_1$ is given (on page 539): $$\gamma...

 
@Venus I wouldn't say that.
 
@Chris'ssis You claim you can evaluate it
 
@Venus I claim we can broad our vision a bit on what a closed form is. I'll give you an example.
 
"Nice form" works as well
 
@Venus $$\sum_{k=2}^{\infty} \frac{\zeta(k)}{(k+2)\cdot 2^k}$$
4
@Hippalectryon No one knows what I have in mind now.
 
5:09 PM
@Chris'ssis I do. You have a brain. :D
 
@Hippalectryon lol :-))))
 
@Chris'ssis Sorry, I'm not interested in this one. I'm more interested in knowing the closed-form of each integral in VR's problem. Anna's thought turns out to be correct, that each integral has no closed-form
Now I become more interested in knowing the answer about her claim on this one
@VladimirReshetnikov As I said, I don't know. But I'am able to prove it using a real method as a combination of them, not the separated one. — Anastasiya-Romanova 秀 Dec 8 at 19:39
 
@Venus The point is that the series above explains what I meant by a broder vision.
@Venus Using Hermite's integral ... (most likely)
 
@Chris'ssis But you claimed in your deleted comment you can prove it
@Chris'ssis Like what?
 
@Venus I was referring to Anastasiya-Romanova's comment.
 
5:17 PM
@Chris'ssis I referred to her comment too. How to use Hermite's integral to evaluate this integral? As far as I know, Hermite's integral can only be evaluated by using contour integration, not real method
 
Have you ever seen this constant? $$\log B=\lim_{n\to\infty} \left(\sum_{k=1}^{n} k^2\log(k)-\left(\frac{n^3}{3}+\frac{n^2}{2}+\frac{n}{2}\right)\log(n)+\frac{n^3‌​}{9}-\frac{n}{12}\right)$$ This one amongs others was considered by Choi and the famous professor Srivastava. Now, if you're aware of it, you can do the series I gave you and find a closed form, otherwise you cannot do it.
 
Congrats to Mike Wojnowicz for his incoming 30 Minutes or Less.
 
I have decided to vote for Thomas, Pedro and Daniel, in this order.
 
@Venus Try to have a broader vision on things :-) Things change during the time, new constants are defined ... so we have new closed forms ...
 
@Chris'ssis How come I see the broader one if the smaller one has not been solved?
@JasperLoy Vote for Jack if you wanna see my real picture as my ava
Provided Jack gets elected ^^
 
5:24 PM
@Venus That is such a funny condition.
 
@Chris'ssis Maybe after election, I'll repost that VR's problem. I think it's not a dup
@JasperLoy Jack's not funny. He is mature and to be honest, he is cool too
 
@Venus I see. Just like Huy, lol.
 
@JasperLoy Only Jack's better
 
@MikeMiller That slut link is so stupid.
 
@JasperLoy I'm so stupid
 
5:39 PM
@user130018 Hello Bart. I am very sad these days. Maybe I will email you to say more.
 
@JasperLoy That's fine. I just have to study for finals this week and next week so I might not respond quickly
 
@user130018 I will just stick to using your weird email address, since that is your primary one now.
 
Hey @DanielFischer I returned the elements like that:
if (m%2==1) m=A[(m-1)/2]
else m=0.5*(A[(m-1)/2]+A[m/2])
j=low
for (i=0; i<high-low+1; i++){
M[i]=abs(A[j]-m)
j++
}
count=0
while (count<p){
min=M[0]
position=0;
for (i=1; i<high-low+1; i++){
if (M[i]<min and i!=position){
min=M[i]
position=i
}
}
return A[position]
count++
}

Could you tell me if it is right?
 
@Alyosha Hello.
 
@evinda Did you find a soolution to yesterday's problem ?
@evinda We just happened to see a median finding alg today in class
In O(n)
 
5:48 PM
Is it me or those winter bash have a slight delay?
 
@MikeMiller Look what I found above.
 
I'm well aware of his existence.
 
@JorgeFernández They do, sometimes several hours
 
@JasperLoy Some dude even made another @TedShifrin account. Weird people uh
 
5:51 PM
@Hippalectryon What do you mean they do? What are you referring to?
 
The difference is that this is an entirely distinct human being named Mike Miller, not a copycat account, @Hippalectryon.
Of course, there are quite a few Mike Millers out there.
 
@JasperLoy bad ping
 
@MikeMiller I am well aware of the existence of several Jasper Loys in this world.
 
Are those common names where you're from?
 
Well, Loy is an uncommon last name here in Antarctica.
 
5:52 PM
@JasperLoy I pointed MikeMiller2 out before
 
@Hippalectryon It was you
 
@BalarkaSen shhhhhhh
 
And later robjohn changed the name to Not Ted Shifrin. :P
 
I should make a Balarka Shifrin account some day
 
I am so sad these days that I feel I cannot carry on living anymore.
 
5:54 PM
Mercy @Hippa
I am already on ignore
 
@JasperLoy Tell living to buy a car. That way you won't have to carry that lazy person around.
:P
 
Why @JasperLoy?
 
@skullpatrol Well, like what you may have heard already, sometimes, I don't think I can get well and go to grad school anymore. I think the chances of me getting well are 0.1, and the chances of me getting into grad school are 0.1, so the chances of both happening are 0.01.
 
Later
 
5:57 PM
@Jasper I do not know what the probability of either of those are. On the other hand, I do believe that they are lower if you do not have some faith in yourself. So I hope you do, and do not worry about the probability, and try regardless.
I hope you still begin your study on Jan 1, since I think it will make you happy.
 
Plus 0.01 is a high probability eitherway.
But yeah, studying gets you to forget about pretty much everything else, so hear hear
 
@MikeMiller Thank you for your kind words.
 
Watch this @JasperLoy
It is just as true for adults.
 
So I have a question.
 
askaway
 
6:02 PM
I am looking at $f:R_s \to R_s$, $f(x)=e^x$. I am not mistaken that it is continuous, open and closed, right? And yet $f(x)=-x$ is not continuous, neither open nor closed
 
I don't know what $R_s$ is.
 
6:18 PM
So soon?
 
@DanielRust Hm... there doesn't seem to be a big list question about applications of elementary linear algebra, and I'm TAing it next quarter. It might be good to have a bunch of them to construct examples with.
(I know the canonical one in linear algebra courses is modeling dynamics with Markov processes and using diagonalization to compute the $n$th state easily. But surely there's more than that.)
 
@skullpatrol I was eating dinner
 
icic
 
Hello!!!

Could someone explain to me the following definition of a vertex cover??

A vertex cover of G=(V,E), an undirected graph, is a subset $S\subseteq V$ such that each edge of G is incident upon some vertex in S.
 
Who is starring random messages in a row....
@Vladhagen ?
Who's polluting the starred board..
 
6:29 PM
Isn't this guy just that ^ identification space, @Mike?
 
Can somebody drop me a hint for (b)?
I don't see how we can use the cube root of unity $\zeta = \exp (2\pi i/3)$.
 
I don't understand your picture, @BalarkaSen, but your answer is correct. (I probably would have done away with $c$, given we know that it's just $a$; the group also has presentation $\langle a,b,c | [a,b] = 1, [a,c] = 1\rangle$).
 
I know my answer is correct, but I think the identification space above is precisely $X$.
 
I can't decode it.
 
Huy
@MikeMiller: What kind of applications are you looking for? I just TA'd linear algebra this semester, so I might have some.
 
6:34 PM
@Huy Any applications outside of math of elementary linear algebra that don't take too long to present. (When I say elementary linear algebra, my students won't have done any more than diagonalization and the singular value decomposition by the end of the quarter.)
 
@evinda Not right. You return A[position], and thus the while (count < p) loop is run only once. If you replace the return with something that adds A[position] to a list, you have the problem that every iteration will find the same position. You'd need to modify your M array so that M[position] is set to something large enough that position will not be used again. And it's somewhat inefficient, $O(p^2)$, where an $O(p)$ algorithm can be used.
 
I'm going to post this as a big-list question at some point, so I invite you to answer it there.
 
Huy
@MikeMiller: Your example being Markov chains or recursions?
 
Because we are identifying S^1 cross {x_0} and S^1 cross {x_0}, the identification space is the square [0, 1]^2 and [0, 1]^2 with opposite ends identified as well as four of the sides from two of the squares are identified @MikeMiller
Oh wait
There is also another identification
 
@Huy Yeah, that's the one that was covered in my linear algebra class back in the day. I'm fairly ignorant of other things.
 
6:36 PM
Sheesh this is getting complicated
 
It's just two donuts sitting on top of each other. Don't make it complicated.
 
Right.
:P
It could've been done just using baby van kampen then.
the space is S^1 \wedge S^1 cross S^1
 
Huy
@MikeMiller: Are you TA'ing LA for mathematicians?
 
I think math students take it, @Huy, but it's a general-audience course. Engineers and physics students have to take it too, for instance.
It's not proof-based, more computation-based.
 
Huy
@MikeMiller: I dislike computation-based. ._.
 
6:45 PM
Me too.
 
Huy
@MikeMiller: When are you posting the question? I have to prepare an answer. :D
 
I dunno yet.
 
Any ideas about the series question, guys?
It's do with using the cube roots of unity to find a closed form of the series below. $$\sum_{k=0}^{\infty} \dfrac{x^{3k}}{(3k)!}$$
 
Huy
@MikeMiller: Please not within the next 15 minutes.
 
It won't be that soon.
I need to get more people than you lined up to answer...
 
Huy
6:47 PM
@MikeMiller: No, please, just me.
 
what question, @MikeMiller?
 
It's not a big-list question if there's only one answer :)
@BalarkaSen I'm looking for non-math applications of elementary linear algebra.
 
oh nah
 
Yes, I know that's your answer.
 
Huy
Why, @BalarkaSen? What do you dislike about linear algebra?
 
6:49 PM
@JorgeFernández So that means if there are 40 vertices...the number to guarantee it is...742?
 
It's the 'non-math' part that upset him.
 
what @Mike said
everything other than mathematics is a waste of time
 
Really? What about eating and sleeping, @Balarka?
 
Huy
Kids these days...
6
 
Is there someone that can help me at NP-complete problems??
 
6:50 PM
eating is waste @Khallil
sleeping can be useful
 
Let me guess, if you dream of math.
 
Huy
@BalarkaSen: I challenge you to stop eating since it is such a waste of time.
 
google [poincare subconsciousness]
 
@Huy i waste a lot of time. i admit it.
 
6:51 PM
Anybody here have any experience with basic graph theory (simple graphs only?). Is there any formula to calculate this? "Five vertices are labeled 1,2,3,4,5. In how many ways can edges be drawn between some pairs of these vertices so that the result is a connected graph?"
 
@Huy I challenge you to stop breathing since it is such a waste of time.
:P
 
Huy
@Hippalectryon: I never considered breathing as a waste of time.
 
breathing might be useful
 
might
 
might
MIGHT
 
6:52 PM
:P
 
@Mike the topology on $R$ who's basis are the segments $[a,b)$
 
Come on guys there is more to life than math.
 
mightematics
 
@skullpatrol is preaching the truth. Listen up, @Balarka kun.
 
You need balance.
 
6:54 PM
@Hippalectryon LOL
 
It is not healthy to have a "fixed mind set" on only one thing @BalarkaSen
 
who cares about health
 
@Studentmath Whose, not who's.
 
@jasper right, thanks
I hate making that mistake. It annoys me when I read it in texts.
 
Your health is what keeps you alive and pain free @BalarkaSen
 
7:03 PM
who cares about being alive
now i am totally trolling you
troll over skullpatroll
 
@Studentmath did you receive my ping about graph theory?
 
@Studentmath I agree with your conclusion on $e^x$ and $-x$.
 
@Mathy yes, but I saw you got help - still unclear?
@Mike actually reconsidering, $e^x$ isn't closed.
 
@Studentmath Not sure I agree. What's your argument?
Oh, I see it.
 
$R$ itself is closed
But- yeah.
 
7:05 PM
Yeah.
Hi, @Behaviour. Do you know a thing or two about applications of linear algebra outside math?
 
@Studentmath Yep, I did get help, but wasn't sure my answer was correct because it was a high number (742).
 
>8( @BalarkaSen
 
@Mathy I actually saw a nice proof of it recently, let me check the book. What was the precise question again?
 
@MikeMiller All applied Mathematics is half Linear Algebra, half Taylor's theorem.
One more downvote on this please, so 20K users can vote to delete.
 
do we know anything about the structure of Homeo(Cantor set) @Mike?
 
7:06 PM
@MikeMiller Or at least it looks like it to me, because I'm not applied.
 
I know that, @Behaviour, but I'm ignorant as to any of it.
Y'see, I'm posting a big-list question about applications of linear algebra at some point...
 
It's funny that you should mention a fixed mindset, @skullpatrol!
I was just watching this video: http://www.youtube.com/watch?v=pN34FNbOKXc. ^_^
 
(Surprisingly, that's not a duplicate.)
 
@MikeMiller
 
No idea, @BalarkaSen. You're talking to the wrong guy.
 
7:08 PM
Compressed sensing involves linear algebra with particular types of matrices.
 
Well, I invite you to post that when the time comes.
 
@Mathy the minimum number of edges so that we can Gurantee that a graph is connected?
 
So was I @KhallilBenyattou
 
@MathyPerson if there are $n$ vertices the answer is $\binom{n-1}{2}+1$
 
The Eng room is all about getting more hats now.
 
7:12 PM
What is the fastest way to compute $$\int_0^{\infty } \frac{ \log ^2(x+1)}{2 x^2+3 x+1} \, dx$$?
 
@Studentmath @JorgeFernández So if the graph had 40 vertices...it would be 742?
 
Asking @Chris'ssis for the value?
 
@Studentmath This was the problem: Let G be a graph with 40 vertices and E edges.

What is the minimum value of E that guarantees that G is connected?
 
@DanielFischer Not really. I was asking for a fast solution. In my research I discovered such questions can be done in a very fast way.
 
@Chris'ssis Sometimes, asking you is a fast solution.
5
 
7:14 PM
@Mathy well yeah, 742. But do you understand why, though?
 
@MathyPerson yes
 
@DanielFischer Sometimes. :-)
 
741 is the maximum number for an unconnected graph. Add 1 to get the minimum number to guarantee a connected graph @Studentmath @JorgeFernández
 
Indeed
Obviosuly considering it is a simple graph
 
Yep, ok. Thanks both of you! @Studentmath @JorgeFernández
 
7:16 PM
no problem
 
Sure, if you have any graph-theory related questions feel free to ping me, I just might find myself useful here :P
 
@JorgeFernández And yes, I did see your changed answer on the boys and girls seating problem
(in reply to your ping) @JorgeFernández
 
I finally have a break for a while. I am waiting at a friend's place waiting for a refrigerator to be delivered.
 
@Studentmath Alright! :)
 
7:20 PM
@DanielFischer let me show you something mind-blowing (first let me check it once)
 
@Studentmath Do you have any advice regarding questions that ask how many ways edges can be formed on a connected graph?
 
@Chris'ssis Mind you, I haven't tried this yet, but I'd try integrating $$\int_0^\infty\frac{\log(x+1)^3}{2x^2+3x+1}\mathrm{d}x$$ along a keyhole contour
 
@robjohn It seems that we have the same hat.
 
@robjohn You mean the cubic version? I only used that previous one since it is related to my research.
 
@Chris'ssis Yep... that sometimes works.
 
7:24 PM
@KhallilBenyattou Here is the prof
 
Just stopping by to say this user is awesome. Great to have folks like this around.
22
 
heh
 
@Behaviour Where is it supposed to take you to?
 
@DanielFischer @robjohn My research shows that
$$\int_0^{\infty } \frac{\text{Li}_{2011}\left(\frac{1}{x+1}\right) \log ^2(x+1)}{2 (x+1)} \, dx=\zeta(2014)$$
 
@Huy You around and ready?
 
Huy
7:28 PM
@MikeMiller: Not even close. ._____________.'
 
@Behaviour very humorous... I bet everyone will agree.
 
@Huy Note that since I'm posting this as a big-list, different applications should go in different posts.
 
@Chris'ssis You forgot the right hand side. $= \zeta(2014)$ if the Mathematica input you posted before was the same thing.
 
Huy
@MikeMiller: I finished writing up a first application, but I'm sure you know of it too.
 
Which is it?
 
7:30 PM
@DanielFischer You knew this integral?
 
If it's not Markov chains, I don't.
 
Huy
@MikeMiller: It's an eigenvalue problem.
 
@Chris'ssis Now the question is, is that specific to $2011$ and $2014$, or is it general?
 
Cool, I'm excited to read about it.
 
Huy
@MikeMiller: But not the Fibonacci sequence!
 
7:30 PM
How many are you going to write up?
 
Huy
@MikeMiller: Three applications came to mind immediately, I'm thinking about how to start with the second.
 
@Chris'ssis No, but I had a glimpse of the Mathematica stuff you originally posted.
 
@Huy Tell me when you've got 'em written down, and I'll post it.
 
@DanielFischer That is just the particular case of a more general case I obtained. I specifically chose that value for getting our year.
 
Huy
@MikeMiller: Sure, if it's no trouble for you to wait a bit. I'll have to take the trash out in the next 30 minutes and then I'll continue if I'm not finished already. I hope I won't delay you for more than 1 hour.
 
7:32 PM
No trouble at all.
I appreciate it.
 
@Chris'ssis Then it's not just a nice curiosity, but a really cool thing. Congrats. May I ask how, roughly, one computes such integrals?
 
@Hippalectryon I wrote something but it isn't right...
@DanielFischer So shouldn't we do it with a for loop?
 
@DanielFischer I do these things every day, they simply come to mind in a natural way, and all together comes from exploiting very simple things. I think Ramanujan did the same (it's just a guess).
 
@Huy Ping me when you're done; I'ma do stuff.
 
@Behaviour you're being sarcasting
 
7:34 PM
@evinda A loop is fine, you just can do better than looking at the entire part for each value by using the fact that the part is now sorted.
 
i'd rather have comments like "this user is arrogant, stupid, and idiot and a complete prat" than sarcasm
i'm actually offended.
 
@robjohn should big-list questions be posted as CW, or have moderators make them CW?
 
Me too @BalarkaSen
 
That link just takes you to your own user page right?
 
@MikeMiller if they are posted as CW, then it saves people flagging and moderators having to make it so.
 
7:36 PM
Yes @JasperLoy
 
@robjohn It seems you cannot make a question CW while posting, only answers.
 
@Chris'ssis That's not what I meant, I meant the techniques one uses, substitutions (which sort), series expansions, integration by parts, or what.
 
@MikeMiller Only mods can make a question CW.
 
@MikeMiller Ah, then flag for a moderator to make it so
 
Alright. Thanks.
 
7:37 PM
@DanielFischer all of them and more than that. I developed specific tools (methods) for handling with some questions I didn't share yet.
 
I dislike some users making an answer CW just because it is trivial. I also dislike the community not upvoting an answer just because it is trivial.
 
I think "Yes, your proof is correct" answers should generally be made CW.
 
Needless to say, all my answers are trivial, and I have made none of them CW, lol.
 
@Chris'ssis Please do share them in the not too distant future. It would be a pity if they would be lost.
 
Yes, but better yet, they should have more content than that. I've never found it impossible to add something to that line.
 
7:39 PM
Now I can go on and talk about a CW complex, and the next thing that will happen is Ben is going to come in and ask me whether I know what a CW complex is. I am still feeling upset over this incident from years ago.
@DanielFischer You can get a copy of her book when it is done. It is not for me though, because it would be too hard.
 
i'd actually prefer if you remove that @Behaviour. it is quite offending.
 
Let it go my friend @JasperLoy
 
@DanielFischer I'm glad you appreciate my work. I'd like to write some articles first (some are about to be published) and then I try to publish a book. It's not that easy with publishing books since I have no math background. Of course, everything must be done in a rigorous way, but still, this won't be a problem. I'm only concerned with my lack of background.
 
You will do it soon
 
@Chris'ssis You need to get a proofreader to correct the English too.
 
7:43 PM
@JasperLoy This won't be a problem. Yeah, I need one!:-)
 
@Chris'ssis If you are my girlfriend, I will definitely do it for you. But you are not, lol.
 
@JasperLoy lolll :-))))))))
@robjohn by the way, can you do the quadratic version I posted above by real methods?
@Hippalectryon you don't wanna miss the integral I posted above.
 
@Chris'ssis Which one ?
 
@BalarkaSen Really? It's just silly to me, not offending. I think I am almost offended by nothing, even though I can be hurt.
 
@Hippalectryon $$\int_0^{\infty } \frac{\text{Li}_{2011}\left(\frac{1}{x+1}\right) \log ^2(x+1)}{2 (x+1)} \, dx=\zeta(2014)$$
 
7:46 PM
That's a funny one
4
 
@Hippalectryon :-)
 
@Chris'ssis Despite your lack of background, your mathematical genius already far surpasses that of many math professors.
 
@JasperLoy well the comment intended sarcasm. if @Behaviour feels i am posting silly answers/silly comments or if he has any other complaints about me he could've just wrote that much. if participation in this site brings along sarcastic offences, i will desist active participation from this point onwards.
 
@BalarkaSen Do you know that it just takes you to your own user page for whoever is clicking on it, not you in particular?
 
Does anyone know if the following is true: If you are given two sequences $a_{n}$ and $b_{n}$ such that $a_{n}b_{n} \geq 0$ and the limits $\lim\limits_{n \rightarrow \infty}a_{n} = a$ and $\lim\limits_{b \rightarrow \infty}b_{n} = b$ then can it be shown that $$\limsup\limits_{n \rightarrow \infty}(-a_{n}b_{n}) \leq -ab$$?
 
7:51 PM
eh
sheesh
i'm such a fool
infinite facepalm
 
@BalarkaSen No problem. But in any case, if you are unhappy with him, you should have asked him why he said that first before getting overly angry.
 
I see no reason to interpret Behaviour's respect for you as sarcasm, @BalarkaSen.
 
i... well... sheesh this is embarrassing/
 
I just watched Good Will Hunting and A Beautiful Mind. Which other old inspiring movies should I watch?
 
i am now doubly angry on him for the joke. grumph.
 
7:55 PM
The only thing that I cannot stand for as regards my work is when someone suggests my work is taken from elsewhere. I prefer to be shot down than to be told (even in a nice manner) such things. I love my work very much (as happened with the proof to Au-Yeung series).
 
@Chris'ssis It will be hard to find it elsewhere, since Ramanujan is dead. It might have come from Ethan though, lol.
 
@JasperLoy :-)))
 
@Mathy what do you mean?
 
Fischer is a common German name.
 
7:58 PM
@BalarkaSen I know. Formerly Coargu Aliquis, iirc.
 
But the similarity in the first names was a cool one @MikeMiller
@DanielFischer oh?
 

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