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01:16
@amWhy o/
 
3 hours later…
04:07
Thanks for the answers to my -1/12 question Nilknarf and Simply!
So, Nilknarf, regarding that proof about the relationship between the Riemann zeta function and the integral from -1 to 0 of those functions, do you know for sure that such a proof is actually something that can be done or were you proposing the idea just as a possibility?
 
7 hours later…
11:39
@Nilknarf
@Dibbs Good morning
@Dibbs I believe I have found said relationship
12:14
$poof$ Im here
Hello lol
Have you not done anything with set theory?
not much at all
Ive had the inklings on what it is from the rest of math and a few pointers on definitions in it but thats it
Do you know any of the nature of ordinals and cardinals?
I tried to learn it once but eventualy i realised I was more a fan of logic itself and higher things like catagory thoery (sine it skips a lot of the work in set thoery)
I've covered ordinals before but it was a while ago and I havent studied them since
12:17
so you can assume no knowlage
You know of $\omega$ and all that?
Hm, well, the basic principle of how I'm using ordinals is as follows:
know of and know are two different things. I have the former.
We have a class of functions $f_\alpha$. I define it as follows:
$f_0(n)=1$
$f_{\alpha+1}(n)=n\times f_\alpha(n)$
$f_\alpha(n)=f_{\alpha[n]}(n)$
And so,
$f_0(n)=1$
$f_1(n)=n$
$f_2(n)=n^2$
$f_3(n)=n^3$
$\vdots$
$f_\omega(n)=n^n$
$f_{\omega+1}(n)=n^{n+1}$
$f_{\omega+2}(n)=n^{n+2}$
$\vdots$
$f_{\omega a+b}(n)=n^{na+b}$
hmm ok
one question
if $f_α(n)=f_{α[n]}(n)$
then does $f_{α+1}(n)=n×f_α(n)=n×f_{α[n]}(n)$ ?
The third rule is meant for limit ordinals.
One cannot take $\alpha[n]$ if $\alpha=\beta+1$, which means we would use the second rule
$\alpha[n]$ denotes the $n$th term of $\alpha$'s fundamental sequence.
The usual FS is given by:
$\omega=\sup\{ 1,2,3,4,\dots\}$
Thus, $\omega[n]=n$
$f_\omega(n)=f_n(n)=n^n$
$f_{\omega+1}(n)=nf_\omega(n)=n^{n+1}$
And so the goal from here on out is "what's the largest ordinal we can construct?"
12:27
so the $f_α(n)$ in the secont rule is different from the one in the third?
also, what does sup stand for?
$f_{\omega^2}(n)=f_{\omega n}(n) = n^{n^2}$
Yes, the second and third rules cannot occur simultaneously
hmm ok
Supremum
Kinda like a maximum + a limit
$\sup(A) = \min\{\gamma : \gamma\ge\delta\forall\delta\in A\}$
For example,
$1=\sup\{0.9 ,0.99, 0.999, 0.9999, \dots\}$
google defines it as the smallest quantity that is greater than or equal to each of a given set of quantities. So basicly the maximum element in the set; but defined using the concept of smallest greater element
As $1$ is the smallest number larger than all elements of that set
@user400188 Ha, yes, that is my definition. But its not equal to the maximum element
12:30
ah yes your right
Note that $\max\{0.9, 0.99, 0.999, 0.9999,\dots\}$ does not exist
As $\max$ finds the largest element in a given set
so when we say $\omega[n]=n$ the set $\{1,2,3,4,...\}$ does not contain $n$
But clearly there is no largest, as the supremum of the set is not within the set itself
@user400188 No, we are saying $n$ is the $n$th term of $\omega$'s fundamental sequence
As you can see, $1$ is the first number in the set that defines $\omega$. $2$ is the second, $3$ is the third...
but if ω=sup{1,2,3,4,…}, and ω=n then shouldnt be not included in that set?
No. By nature, $\alpha[n]$ is in the set, as $\alpha[n]$ is the $n$th term of the set
And $\omega\ne n$
@Mathmore Hello and welcome to my realm
12:35
so whats the difference here between ω=sup{1,2,3,4,…} and ω={1,2,3,4,…}
in both cases it appears that ω[1] would be 1 and ω[n] would be n
unless the []'s are not conventional brackets, and stand for something else
Thanks!
welcome @Mathmore
Hello!
Its just different ways to write the same thing
Thanks!!
12:36
Which is the problem when trying to use ordinals in this manner
supremum of the set {1,2,3,4,...} ?
If we don't define how an ordinal is broken down i.e. we don't give it a fundamental sequence, then we can't use it quite well
@Mathmore Yes, we are doing ordinally stuff
1=sup{0.9,0.99,0.999,0.9999,…}. Doesnt that imply that a single set has just 1 value when we take the sup of it? As opposed to the multiple we obtain when we write ω[n]
hahah!
@Mathmore as you can see, I am rarther new to this stuff
12:38
Okay. So you say that the supremum of the set of naturals exist?
@Mathmore Von Neumann ordinals. The supremum of every set of ordinals is another ordinal, except for the supremum of all ordinals
Okay. I will have to study this. I can't comment anything.
No no, that's not what I meant. For example,
$$1=\sup\left\{ \frac12, \frac12+\frac14, \frac12+\frac14+\frac18, \dots \right\}$$
^ As you can see, there are infinitely many sets who's supremum is $1$.
Likewise, there are infinitely many set who's supremum is $\omega$
To make any sense of $\omega[n]$, we have to assign it a "fundamental sequence" to which we may pull values from
@Mathmore Its open discussion, we learn as we go/chat, so feel free to join in, even if you don't know much
so $\omega$ is a number and not a function, and $\omega[n]$ is something that starts at the first element of the set it is defined for and has a sequence associated with it
Well, it is the case that:
$$\alpha=\sup\{\alpha[1], \alpha[2], \alpha[3], \dots\}$$
And yes, $\omega$ is a "number", as are all ordinals
12:43
hmm, so $\alpha[1]$ here would be $\alpha[1]$ and so forth for each element?
and $\alpha$ on its own is a number associated with the whole thing
cool, Ive understood the notation
@SimplyBeautifulArt That's cool.
12:44
Though for me to create any finite numbers out of this, I can't just say "$\alpha$" for some really large $\alpha$ without defining $\alpha[n]$
makes sense. $\alpha$ only appears to be a label for the thing on the right.
Well, its mostly a label for me. For the purposes of large finite numbers, I mostly need syntactic ordinals
That is, ordinals defined by syntax. For example, I could've just said $\omega[n]=n$ without ever introducing the concept of sets and fundamental sequences
I see I'm going to get used to a lot of notation differences
hmm actualy, the notation doesnt idffer, it just leaves a lot out
Anyways, these ordinals are useful for their well ordering as well:
$0<1<2<3<\dots <ω<ω+1<ω+2< \dots<ω2<ω2+1< ω2+2<\dots<ω3<\dots < ω^2<\dots$
$$\omega2=\sup\{\omega+n| n\in\mathbb N\}$$
$$\omega3=\sup\{\omega2+n|n\in\mathbb N\}$$
$$ω^2=\sup\{ωn|n\in\mathbb N\}$$
$$ω^2+ω=\sup\{ω^2+n|n\in\mathbb N\}$$
I feel like we got big really fast just then
12:50
Nah. $f_{ω^2+ω}(n)=n^{n^2+n}$
So its not so large yet. It also makes it somewhat obvious how $n$ relates to the $ω$'s
isn't $\omega$ bigger than all the naturals by that first line?
then $\omega 2$ larger than $\omega$ and so on?
Yup
Be back in a bit, breakfast
alright
enjoy it :)
Welp, I'm back
to clarify; is $\omega 2=sup\{\omega+n|n\in N\}$ the act of adding any natural to $\omega$ then taking the supremum?
to me that means we could add the last natural then increment one further, and that this is $\omega 2$
that was a short breakfast
12:56
I don't eat much
@user400188 There is no last natural number
simply: gulps air "I'm done"
If there were a number directly before $ω$, it would be $x$, where $ω=x+1$
hmm ok
However, there exists no such $x$. You can prove by contradiction by assuming there is such an $x$ and using $ω=\sup\{1,2,3,\dots\}$
Is omega a complex number?
12:58
oh; x would be in the set {1,2,3...}
@Mathmore $ω$ is a transfinite number. Positive and larger than all finite numbers
and omega - 1 would not be in the set
@user400188 And necessarily there will exist $y>x$ for all $x$ in the set.
Oh! interesting
so its implied that x is both in and not in that set
12:59
What is a transfinite number?
Kinda like an infinite number
Okay.
@Mathmore You know about supremums?
Yup!!
Supremum is the least upper bound
Well, $ω=\sup\{1,2,3,\dots\}$
So $ω$ is the least number larger than any finite number
13:00
Yup that I figured out from this chat!
And... brb. Nature calls lol
Hahaha
I intend to read Halmos's Naive set theory soon. I have drastically less knowledge about set theory.
probaly more than me
that said; have you read any logic textbooks before?
13:03
@user400188 No. I haven't.
I just rely on the opening chapter of a standard Analysis/Topology text book for set theory.
I'm finding they make a lot of math easier. You only have to read one then you can understand so much more quickly. Particularly proofs and set theory.
@Mathmore Fun
@user400188 Haha
Well, perhaps you've noticed the pattern by now
I used to find topology so much fun, I'm kind of sad that I'm finding it less interesting now than other topics.
Ill probaly return to it another day though
@user400188 Thanks! I will definitely take a look.
You have some suggestion?
a friend of mine would reccomend a book named Sweet Reason
13:06
$$f_{ω^{ω^{ ω^3+3}5+ω}8}(n) = n^{n^{n^{ n^3+3}5+n}8}$$
You perhaps want an interesting problem to get your love for topology back.
its a paid for book; but you can access it from sites like library genesis
Okay will check out thanks!
Authors are Tom Tymoczko and Jim Henle
@user400188 PBS's Infinite series has an episode on topology
13:07
I havent checked out much of PBS's stuff
I have heard about Infinite...
I watched a few physics vidoes from it and found them too opinionated
Detective using Mahts?
Maths*
I like their math videos a bit
They also have a few on how ordinals relate to finite numbers in manners other than the ones I'm showing you
13:08
personly I like the vsauce video on them
you cant really learn much from vsauce, but it can certainaly give you an appreciation
and Ive yet to find a mistake in any of thier math videos. Its nice to know your not been fed incorrect stuff
Yeah lol. All the awesome math xD
I suggest NPTEL video courses.
Real Analysis, Linear Lagebra, Measure and Integration, Functional Analysis, Complex Analysis covered very well there.
wow there page looks good
I am following Measure and Integration currently.
It's going good. :)
maybe Ill give some of there courses a listen tomorrow.
But for now I think Ill be heading off to bed. (Its 11:17 pm here)
13:18
g'night
Oh! Sure. Where do you live anyway?
Australia
Good night. :)
Night @everyone
Thanks for the introduction to ordinals @SimplyBeautifulArt
13:19
@SimplyBeautifulArt Have you studies dense subsets?
studied*
I know of them
Trying to solve this integral right now:
1
Q: Closed form for ${\large\int}_0^1\frac{\ln^4(1+x)\ln x}x \, dx$

John BaezCan someone compute $$ \int_0^1\frac{\ln^4(1+x)\ln x}x \,dx$$ in closed form? I conjecture that the answer can be expressed as a polynomial function with rational coefficients in constants of the form $\operatorname{Li}_n(x)$ where $n$ is a natural number, $x$ is rational, and $\mathrm{Li}_n...

A question I encountered : Is the subset of set of all 2 \times 2 matrices with both eigenvalues real a dense subset?
@SimplyBeautifulArt Oh okay.
@Mathmore Yeah, I'm not super familiar with that
Np
How are you tackling that integral?
$$\int_0^1\frac{\ln^4(1+x)\ln(x)}x~\mathrm dx=\lim_{s\to0,t\to-1^+}\frac{d^4}{ds^4}\frac d{dt}\int_0^1(1+x)^sx^t~\mathrm dx$$
13:32
hello people
@F.Tasos @kingW3 Hello and welcome to my realm
greetings from greece
Hm, I can't seem to figure out how to take the derivative so nicely
So $...$ doesn't work here?
I mean MathJax.
Oh, MathJax works, you just gotta install it
13:35
@SimplyBeautifulArt I can't see what you wrote there.
Can you tell me how to?
Mathmore, it's chatjax that you need for using mathjax in any chatroom on site.; there's a bookmark you can add to your browser (find it on the general Mathematics chatroom).
See this and below
More or less, follow the images I posted if you use Google Chrome
Thanks @amWhy @SimplyBeautifulArt
$\LaTeX$ in chat: tinyurl.com/cfqcvpc
@amWhy Put https:// in front
13:43
I added the bookmark to my browser.
I use mozilla. I am seeing your images in the link you've provided. @SimplyBeautifulArt
Go to your bookmarks and click on "start Chatjax".
Awesome!
Worked.
@Mathmore Yay!
$$\color{red}n\color{orange}i\color{yellow}c \color{green}e\color{blue}l \color{purple}y\text{ done}$$
13:51
This chat room seems so cool. Everybody is so friendly.
On the website though I have to be afraid while typing. :P
@SimplyBeautifulArt How did you do that? "Nicely done" ?
\color{red}{n}
\color{orange}{i}
etc.
Also, you have to put spaces in the code or else it'll break.
$$\begin{align}\int_0^1\frac{\ln^4(1+x)\ln(x)}x~\mathrm dx&=\lim_{s\to0,t\to0^+}\frac{\mathrm d^4}{\mathrm ds^4}\frac{\mathrm d}{\mathrm dt}\int_0^1(1+x)^sx^{t-1}~\mathrm dx\\&=\lim_{s\to0,t\to0^+}\frac{\mathrm d^4}{\mathrm ds^4}\frac{\mathrm d}{\mathrm dt}\frac1t~_2F_1(-s,t;t+1;-1)\end{align}$$
Huh, surprised this is short enough not to break
Gosh dang it, why you no break? I try to make example out of you!
13:54
$\color{blue} a \color{red} w \color{yellow} e \color{purple} s \color{green} o \color{blue} m \color{red} e$ mate!
Hm, where is @Nilknarf this morning. Missing out on the chatroom lol
Ah I see you using two variables. hmm
Yeah, I doubt I'll be able to complete the integral
13:56
What is $_2F_1$ ?
Hypergeometric function
Okay.
Special function stuff
I see.
pardon me for asking but is there a special room for functional analysis ?
14:00
No idea
thanks anyway
@F.Tasos I would be interested to join one!
@F.Tasos I am unsure, but I believe functional analysis has been mentioned in this room:

 Calculus and analysis

For questions about calculus, real analysis, functional analys...
thanks @SimplyBeautifulArt i appreciate it
Subbranch of analysis. :D
Not my area of knowledge sadly
Hello,@SimplyBeautifulArt Did you try doing partials with $u=\ln^4(1+x)$ and $dv=\ln x/x$?
No, I gave up on that integral lol @kingW3
Oh nevermind :P
14:13
@F.Tasos I have done basics of Hilber space. But no idea on this. What did you try?
someone answered
Hilbert*
Yup I can see that.
I think we can use following things : 1) In metric spaces, a space is separable iff it is second countable. 2)Gram-Schmidt process to generate basis (as suggested by the answerer on the OP). What say?
@SimplyBeautifulArt Perhaps you can learn from others here?
Yes, I do listen in on the conversations :-)
im trying to figure out why the span of projections is dense in U^{\bot}
if i cant do it in 10 min ill grab pencil and paper
14:24
Since $L^2[a,b]$ is separable, it is second countable as well. So it has a countable basis. Now we have $e_n$ as an orthonormal set so it is linearly independent.
that is true
From here on I'm thinking what can we get...
Either $e_n$ is the basis or we can extend it.
I give up on my way currently.
 
1 hour later…
15:41
@Simply need help getting the intuition on something
$$\nabla(|u(x,y)+ iv(x,y)|)^{p} = p(p-1)|)|u(x,y)+iv(x,y)|^{p-2}| \nabla f|^{2}$$
                                                        ^ If $f$ is harmonic and real-valued on $U \, \subset \mathbb{C}$ and if $f$ is nonvashing  then ^
@Zophikel ?
You need to prove that?
@Simply yeah i'm trying to get the geometrical intuition, I already know a way to prove it @Simply
If you have a function f, think of the Laplacian of f at x as a measurement of how close you are the average value of points around x. For example, if the Laplacian of f is 0, then you have that u(x) is exactly equal to the average value of u on a ball around x.
^ I know that's the intution behind $\nabla$
@Simply you have any ideas, been wrapping my head around this
Hm, I don't think I have a good explanation for you. :) You are extending to places I haven't gone.
@Simply :) I found a couple of ways to define but I feel like my feel on theorem is too formal :(
 
1 hour later…
16:52
Hello all!
@Dibbs In response to your message to me: yes, the proof can be done (in fact, it seems that @SimplyBeautifulArt has already done it for you, so there's not really much more I can do to help you).
@Typhon Hi!
@Nilknarf what do you want? :-)
Just saying hi since you entered the room
no i didnt....
Please don't tell me you didn't actually enter the room
Dammit
I need to start assuming that whatever the sidebar shows me is false
SBM
SBM
Hello and bye 22:25 today was really busy
16:55
I'm so sorry. :(
@SBM Hi!
@Nilknarf s'okay.
17:45
@Simply
0
Q: Geometrical Intution behind $\nabla(|f|^{p}) = p(p-1)|f|^{p-2}|\nabla f|^{2}$

ZophikelIn the text "Theory of Functions of One Complex Variable", I'm having trouble verifying the way I expressed the Laplacian Operator, and generalizing $(1.)$ to functions of more then one complex variable following Proposition in $(1.)$ Also I'm having trouble establishing the geometrical intuition...

                ^ Can't wait for answers
-1
Q: Is there a multivariate integer function f(x,y) that returns the number of factors of y in x with a closed form?

TyphonI'm looking for a simple function in terms of the elementary and exponential functions that when passed an integer x and integer y, it returns the number of times that y can be divided from x such that the result is an integer. I believe that it is something along the lines of $\lfloor\log_y(x)\r...

need answer
plz
@Typhon I know nothing about the theory of numbers
@Zophikel i didnt ask you to answer it
@Zophikel besides. it isnt number theory.
@Typhon you put it under number theory
17:50
only so people would see it
Gosh darn notifications lol. When you get a text in the middle of your game x.x
lol
be back later
God wtf
An enemy snuck behind my defenses T_T
lol @Simply
I try to be good at video games lol
 
2 hours later…
19:42
@SimplyBeautifulArt Could you share your proof with me? :D I'd really like to see how you did it.
 
2 hours later…
21:46
@Dibbs I've already posted it to your question:
https://math.stackexchange.com/questions/2252550/integrating-the-formula-for-the-sum-of-all-natural-numbers/2337019#2337019
22:06
Oh my bad. I misinterpreted your post to mean that you had found a different proof related to the topic. Sorry about that!
No problem @Dibbs
And you welcome to stick around about whatever. I'll be unresponsive for a bit though, I'm a bit busy
 
1 hour later…
23:26
@Dibbs By the way, you do realize that:
ζ(-0) ≠ 1 + 1 + 1 + ...
ζ(-1) ≠ 1 + 2 + 3 + ...
ζ(-2) ≠ 1² + 2² + 3² + ...
ζ(-n) ≠ 1ⁿ + 2ⁿ + 3ⁿ + ...
@Simply how does this look
In the text "Function Theory of a Complex Variable", i'm having trouble proving the following relation in $(1.)$


$(1.)$

Prove that if $f$ is holomorphic on $\text{U} \subset \mathbb{C}$, then

$$\nabla(|f|^{2})=4 |\partial f / \partial z|^2$$


$$\text{Lemma}$$

The following observations can be made on $(1.)$

Recall:

$$\nabla(|f|^{2})=4 |\partial f / \partial z|^2$$


One can observe in $(2.)$

$(2.)$

$$\nabla^2f(|u(x,y) + iv(x,y)||u(x,y) + iv(x,y)|) = 4 |\partial f / \partial z|\partial f / \partial z|$$
                       ^ Some very interesting problems in my CA Book that i'm reading out of
$$\nabla \cdot \nabla f(|u(x,y) + iv(x,y)||u(x,y) + iv(x,y)|) = 4|( \nabla(f(z))|u(x,y) + iv(x,y)||( \nabla(f)|u(x,y) + iv(x,y)|$$
^ identified some errors i'll have to define some of the notiton I used to manipulate the differential operators used in the proof
23:44
Hm, it looks a little messy, though I'd have to tidy myself up with more studying to understand everything you are doing @Zophikel
@Simply yeah I made some mistakes i'm tidying up some things, oh @Simply you've done lots of mutivarible calc/ mutivarible analysis
Nah, I haven't done much serious diving into multivariable stuff. I just know lots of random things, per chance such random things happen to be related to multivariable calculus, but I haven't done such studying.
@Simply your eventually going to have to get serious in CA and it has lots of connections with DG and Multivariable Calc
:) it really makes the theory beautiful
Yes, I can imagine
@Simply I've good a couple books you might love :)
@Simply it's been cleaned up a bit :) mathb.in/147666
                                       e                     ^ It looks look the conjecture may be true :)
@Simply do you have a good gauge on it

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