Lasertooth
Level 22 Mixist
 
PDF Format
3rd/11

 
Uncommonality 
36th Σ4.951

 
Preciousness 
15th Σ5.560

 
Iniminitible 
48th Σ4.845

 
Masochism 
28th Σ5.310

 
Rarity in Pants 
28th Σ5.255

 
Professor Littlewood's Secret Prime Number Stash
 
  28th/128   Σ25.920   Oct 8th 2023 4:53pm
 
 
I'd been curious to try submitting to the PDF format, and was happy to see it in this battle, but I wasn't sure how to approach it without a bitpack. Ultimately, I realized two things:

1) the type of PDF I'm most experienced with making is an article about math;
2) if anything, the theme of this battle is "rarity".

So here's a short exposition on one of my favorite Very Rare phenomena in math. No background in math is assumed.

8
12
46
8
13
 


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177984
Level 10 Playa
VirtualMan
 
 
post #177984 :: 2023.10.18 9:32pm
  
  cabbage drop and Lasertooth liēkd this
The slot machine analogy blew the bits out of my mind. I enjoyed your paper enough to do more research—because I wanted to know whether or not the statements in your paper were true.

https://en.wikipedia.org/wiki/John_Edensor_Littlewood#Work

The world might be a better place with more bite-sized math papers like this. Thank you.
 
 
177992
Level 22 Mixist
Lasertooth
 
 
 
post #177992 :: 2023.10.19 1:07am
  
  cabbage drop and VirtualMan liēkd this
After a difficult few days of grading precalculus exams, it means a lot to hear this. Thank you very much!

For more on the sordid history of the number that appears at the end, see also

https://en.wikipedia.org/wiki/Skewes%27s_number
 
 
178399
Level 31 Chipist
kleeder
 
 
 
post #178399 :: 2023.10.29 5:31am
  
  cabbage drop and Lasertooth liēkd this
i rly liked this.
i didnt expect to find this here but now im positively surprised
 
 
179358
Level 21 Mixist
SnugglyBun
 
 
 
post #179358 :: 2023.11.20 10:33am
  
  cabbage drop and gotoandplay liēkd this
is it just me or is PDF going to become the smart people's format?
 
 
179830
Level 29 Chipist
funute
 
 
 
post #179830 :: 2023.11.30 9:13pm
  
  cabbage drop and Lasertooth liēkd this
YEA MATH
 
 
179831
Level 22 Mixist
Lasertooth
 
 
 
post #179831 :: 2023.11.30 9:38pm
  
  cabbage drop liēkd this
YEA
 
 
180560
Level 19 Mixist
Lint_Huffer
 
 
 
post #180560 :: 2023.12.09 11:03am
What I would find most interesting would be a plain-English explanation of how Littlewood was able to establish his proof without actually graphing the prime counting function to x=10^316.
 
 
180566
Level 22 Mixist
Lasertooth
 
 
 
post #180566 :: 2023.12.09 12:06pm
  
  cabbage drop liēkd this
Here's an explanation adapted from here
. (I also skimmed Littlewood's original paper
, but it's not my field of expertise and it's in French, so it was a pretty rough skim.)

Imagine a bunch of wheels, each with an arrow pointing from its center to its edge, spinning at different, unrelated speeds. Eventually -- and it might take a very long time -- there will be a moment when all the arrows are coincidentally pointing in the same direction. It's worth taking a minute to think about why this is true for 2 or 3 wheels. Importantly, we know that this happens even if we don't know exactly how fast all the wheels are spinning -- we just won't be able to predict exactly when.

There is actually a formula which can be used to calculate the prime counting function precisely. It works by starting with the approximation mentioned in the main entry, the logarithmic integral function, and then adding an infinite series of smaller and smaller corrections to it. The biggest of these is always a negative number, which is why, at the outset, the prime counting function is smaller.

But you can think of the rest of these corrections as roughly described by wheels with arrows on them, which rotate as we move through the number line. For each correction, when its arrow is pointing up, it's a positive number; when the arrow is pointing down, it's a negative number; as the wheel spins, it oscillates between plus and minus. (The rates at which these wheels spin are a sequence of numbers just as mysterious as the prime numbers, so this formula isn't the most useful for direct computation, but it's a valuable change of perspective.)

So the essential principle of Littlewood's argument was the idea at the beginning of this comment: eventually, enough of these corrections are going to coincidentally line up pointing in the positive direction that they'll push the prime counting function above the li(x) approximation.

(The biggest problem with this analogy is that there are now infinitely many wheels, so we can't talk about them all lining up at once. The question is now a trickier one of getting enough of them to line up. But the idea is similar.)
 
 

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