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Ovi
12:44 AM
@SimplyBeautifulArt Have you ever seen proofs of number theory statements using complex analysis?
They are so cool :D
 
:O
I imagine!
So hell ya hit me up!
Oh, wait
are you talking about analytic number theory?
 
Ovi
Don't think so
Well a problem which I saw in my book
is to prove that if $A$ and $B$ can be written as sums of squares, then AB can also be written as a sum of squares
sums of 2 squares*
 
I'm listening
 
Ovi
Well let A = m^2 + n^2 and B = p^2 + q^2
Let alpha = m + in and beta = p + qi
 
Whoa, wait
NO WAY
XD
 
Ovi
12:47 AM
?
 
ok, keep going
 
Ovi
so A = |alpha|^2, B = |beta|^2
Then AB = |alpha|^2 * |beta|^2 = |alpha * beta|^2
 
Yes, I understand
 
Ovi
ok
The proof is simple, but its really cool I think
 
:D That's nice
yes, of course
2
Q: Is the set of all ordinals producible through ordinal collapsing functions countable?

Simply Beautiful ArtI was recently learning about ordinal collapsing functions, which are a systematic way to produce very large countable ordinals. Before I talk about collapsing functions, I will briefly explain some ordinals: $$\epsilon_0=\omega^{\omega^{\omega^{\dots}}}\bigg\}\omega\text{ powers going up}$$ $...

 
Ovi
12:51 AM
@SimplyBeautifulArt So did you figure out the answer from the comments?
 
I believe the first comment is correct
but its still hard for me to accept
in Mathematics, 2 mins ago, by Simply Beautiful Art
@AkivaWeinberger So a countably finite amount of operations that always map $\alpha_n$ to $\alpha_{n+1}$ for $\alpha_n<\alpha_{n+1}<\omega_1$ will result in some $\alpha_\beta<\omega_1$?
So that's true?
 
 
1 hour later…
Ovi
2:10 AM
@SimplyBeautifulArt Well unfortunately it's way over my head. I was just wishing you luck to find the answer :P
 
haha
Ok then
@Ovi What part is over your head may I ask?
 
Ovi
@SimplyBeautifulArt Well I haven't studied that subject at all so I'm not familiar with any of it. Plus, I've got this large glaring gap in knowledge when it comes to infinite sets. I know the layman definition of aleph null and omega, but that's about it.
 
Ah
Hehe, that's the same as me, except I got way better overnight due to the fast growing hierarchy
 
Ovi
I haven't even convinced myself yet of the uncountability of the reals xD
 
Hm, may I try to convince you?
 
Ovi
2:14 AM
I've seen the proof in passing, but I've never sat down and absorbed it
Sure
 
The amount of reals is represented by the amount of possible decimal expansions you could have, right?
 
Ovi
Alright
 
Every decimal expansion is actually just a string of natural numbers
 
Ovi
Yes
 
And the combinations of how many ways you can rearrange a set with cardinality S is equal to 2^S which is strictly greater than S
(indeed, take two numbers. How many ways can you rearrange these two numbers, excluding the empty set?)
And if you think about it, every decimal expansion is just a combination of natural numbers
Thus, the cardinality of the reals is equal to$$2^{\aleph_o}$$
which is directly uncountable
 
Ovi
2:23 AM
Sorry had to go for a sec
gonna read it now
Well, you kindda have to just believe that |P(S)| = 2^|S| still holds when S is an infinite set though
Is that an axiom?
 
I believe so
 
Ovi
And I know that this sounds weird but
Don't we also need to prove that $$2^{\aleph_o} \not = \aleph_o$$?
I mean I don't know how raising 2 to infinity works :P
 
Well
proofs usually follow roughly from Cantor's diagonolization argument.
And the most we can deduce while staying consistent is that $2^{\aleph_0}>\aleph_0$
 
Ovi
Hm ok
 
Indeed, $2^\alpha$ for any infinite cardinal could be any cardinal larger than alpha
 
Ovi
2:30 AM
Yeah I think I was supposed to learn all this stuff in a class called Discrete Math
 
Ovi
But unfortunately I took it as a 6 week summer class and we covered like 60% of the material
So I have some really awkward gaps xD
 
but none of that should be necessary for figuring out things like ordinal collapsing functions
@Ovi same
 
Ovi
Oh
Well you are not about to graduate with a math degree xD
 
Ovi
2:31 AM
you still have time
 
Ovi
lol
 
As you can see in the playlist, this guy's videos have to cover diagonolization and higher ordinals than basic omega for you to fully use fast growing hierarchy
@Ovi And if you remember my large number coding contest, well, I'll leave it to you to understand what $\epsilon_0$ is and how amazing it is that some people (@user21820 @Deedlit ) are able to come up with functions at that order of FGH
 
Ovi
haha
The guy in the videos explains stuff very clearly though
 
yes
I like his videos :D
May the extremely large numbers be with you and have a good night
As I shall take my leave
XD and I don't think watching all 24 videos straight is good, so take breaks @Ovi , especially when you feel your mind falling apart
 
Ovi
2:42 AM
Haha
Good night @SimplyBeautifulArt
 
 
4 hours later…
6:42 AM
@amWhy Actually mission is not accomplished; the first linked post is not deleted, and I can't even vote to delete it because I'm the only downvoter. Sadly. But if you wish to, please help me check that the argument is irreparable. Thanks a lot! =)
@SimplyBeautifulArt @Ovi: PA is unable to prove a well-ordering of length φ[1](0). My entry used a well-ordering of length φ[2](0). Deedlit's entry would (assuming ZFC is meaningful) use a well-ordering of length so long that it can't be described using only countable things. I currently have a way of getting much further than φ[2](0) but haven't fully analyzed it yet!
Yea it's tiring hahaha..
 
 
5 hours later…
11:52 AM
@user21820 I....uhh....
O.O
 
 
6 hours later…
5:29 PM
@projectilemotion Hey man
If you were interested in some videos on crazy large numbers: youtube.com/…
@Ovi I don't think I'm going to post an answer here: math.stackexchange.com/questions/2177862/…
But I think people are fascinated because they find it very interesting that you can have complex numbers in the exponents.
 
Ovi
@SimplyBeautifulArt Haha I just came in the room to ask if you have an opinion it
But again I didn't get the notification for some reason lol
 
Lol, way ahead of you @Ovi
You don't get notifications if you are fully out of the chat
they will reach the main site in about 20 minutes if you don't go online
 
Ovi
ohhh
ok
So do you yourself find that equation fascinating?
 
Have you enabled desktop notifications?
Yes, I do
It's why I started learning calculus
 
Ovi
ah right xD
well I used to find it super fascinating too
 
5:41 PM
lol
 
Ovi
But then I was reading the complex analysis book, and out of nowhere, they just said "ok, e^{i \theta} = \cos \theta + i \sin \theta"
So I'm like "ok, well if you're gonna define it that way..."
 
Well the idea is to define it somehow
and prove it is holomorphic on C
 
Ovi
Yeah I guess I'll be fascinated again when I learn all the reason's why it's nice to define it that way :P
 
well, it's the only way to define the exponential function if you require it to be holomorphic
and holomorphic is very important, as it leads to things like allowing you to use the exponential function in the residue theorem or Cauchy's integral formula
 
Ovi
Is it possible to define it so that it's just continous on C, and only differentiable on the real line?
 
5:46 PM
Sure...
But all that becomes bad to use when you reach integrals and stuff
 
Ovi
Ok, I'll reevaluate after I learn about the residue theorem and Cauchy's integral formula :P
 
Haha, and for the first weak this year, I've managed to not be in the top 5 on the weekly leaderboard
 
Ovi
:O
Just curious, if you don't answer any questions for a few days, do you have enough posts that you just get a contionus stream of reputation from your previous posts?
 
Not a super lot
but maybe like 100 rep without doing anything that day max so far
 
Ovi
:D
 
5:50 PM
If I'm serious and I get lucky for 10 minutes, I can get 200+ rep, just in 10 minutes
 
Ovi
How so? It's hard to make an answer that gets 20+ votes, no?
 
:-/
I only need 10+ votes ;)
and I can produce many answers many times fast
 
Ovi
Haha nice :)
 
So the question is what am I doing now?
And the answer is I'm still trying to get comfortable with my fast growing hierarchy + Ordinal collapsing functions
 
Ovi
Did you finish the whole youtube playlist?
 
5:57 PM
of course
in one sitting too
 
Ovi
Haha
Is this (and googology) a major field of study, or just something mathematicians do on the side?
 
I don't really know
But I suppose you could say its a subset of computational complexity
 
Ovi
Hm ok
 
6:36 PM
@SimplyBeautifulArt Thanks, I favorited the channel so that I could go look at it sometime.
 
@projectilemotion :-)
 
 
2 hours later…
8:59 PM
@Deedlit I need help perhaps, and this may interest you more than the last question
0
Q: Does there exist a computable function that grows faster than fast growing hierarchy?

Simply Beautiful ArtDoes there exist a computable function that grows faster than fast growing hierarchy for every 'reducible' ordinal $\alpha$? Or does it follow that fast growing hierarchy grows as fast as any computable function? I honestly can't figure out how to even understand how I could tackle such problem...

 
 
2 hours later…
10:46 PM
Hm...
Perhaps I shall do a twenty dollar contest of who can make the largest number on a white board (the kind that's big and on the wall) after most testing is over
because I want to see what random people come up with XD
 
11:37 PM
Hi. :)
 
Hi @SirJony :-)
What are you studying?
 
Calc/Analysis
More specifically right now, infinitesimals
Hopefully I can finish all the exercises regarding that by the end of this week.
 
Then I'm on to continuity.
 
I've never actually learned infinitesimals and equivalences in a "class" type of thing, but I just picked it up
since my calculus class was less proofy high school stuff
 
11:43 PM
I'm following an exercise book, so when I get to the next section, I use multiple sources to learn about it before solving it and then going on the the next one.
 
Hm, sounds like a good though tedious learning method
I usually try to catch onto topics in the middle of some area of mathematics, often without having the pre-requisites, and just building from there
 
I realized that no book covers everything and I need to use multiple sources anyways, so I might as well attempt to solve problems of increasing complexity and new topics as I go through the book.
 
You could say I start at the middle of the meat and work backwards and forwards simultaneously XD
 
I'm going to college in Fall so I'm trying to get a (more-less) solid understanding of Calc/Analysis so I can transition into the rigors of college. I don't want to have the "middle" knowledge when the proffessors will be talking about the "previous".
I'd rather have "previous" first (better yet, "middle" too!).
 
haha
well, I picked up on calculus in 9th grade, so I suppose I have more time than you
 
11:48 PM
I'm technically in 10th, but I'm skipping 2 years. :)
 
;) Nice
Dual enrollment?
 
No, as a homeschooler I can write my diploma earlier than 12th grade. Many public college don't admit students who aren't of college age, so I'm going to a private college.
 
Ah, that also makes sense
Do you know how to code?
 
C, C++, Swift, and a little Java.
So, yes, a bit. :)
 
Want a fun challenge?
(at least sorta fun to some people)
 
11:52 PM
I guess. Depends on how long it'll take.
Give it anyways. :)
 
In 256 characters, not including whitespace, code the largest number you can
 
int main()
{
unsigned long long x = 0;
--x;
return 0;
}
Like that?
Oh wait, double is bigger I think.
 
Sure
Could you take me through what your code does? Since I don't do C++
 
long long is a large-int type. unsigned means that numbers are only positive. When x = 0, the memory sees this as 00000...000 (I don't recall how many 0s) in binary. If we decrement (--x) it underflows, causing 11111...111 which is as largest number representable with a certain number of bits.
everything else is just boilerplate C code.
 
oh, sorry
 
11:58 PM
Like the return 0; and stuff
sorry for what?
 
You have infinite resources available, but you must produce a finite number
and your code must produce one finite number per input
As in no random number generators
 
Oh!
 
haha, it would be a trivial contest otherwise
 
Yeah. :P
 
And just a heads up, 10^10^10^10^... a billion times is small in these contests
 

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