from Hacker News

Can all books be found somewhere within the number Pi?

by jkbyc on 3/14/15, 10:48 PM with 29 comments

  • by brudgers on 3/15/15, 4:13 AM

    The idea of encoding a book as a string is incoherent once we look at it with intellectual rigour. How are images in illuminated manuscripts or graphic novels encoded? What does "all books" even mean? Are we talking about each individual artefact past present and future or some idealized representation of each: e.g. is my current copy of Catcher in the Rye encoded separately from the copy I was assigned in 10th grade English class?

    It's all a matter of interpretation.We can just as easily choose a different arbitrary encoding and claim to have found all the books in π. There's no need to make things complicated. We are free to pick any interpretation we want once we are claiming that numbers represent books. Let:

      B = {b1, b2,...bn}
    
    Such that it contains the set of all books. And let:

      def Find-books(num)
          if 3.14 < num < 3.15
          then return B
          else return "all the books not found"
    
    The article assumes that there is some natural way of encoding books. But digits of π are not Unicode or Ascii characters. Though we can interpret a digit or string of digits as such, that encoding is arbitrary not a property of the natural or mathematical world.
  • by plikan13 on 3/15/15, 11:19 AM

    Yes, but the number which indexes the position in PI where your book starts will probably be longer than the book itself.
  • by BuildTheRobots on 3/15/15, 12:24 AM

    Theoretically, everything can. And there's a FUSE implementation: https://github.com/philipl/pifs
  • by axblount on 3/15/15, 5:53 AM

    The question is: is pi a 'normal' number? It's an open question. Note that it's not particularly difficult or illuminating to generate a normal number, example: 0.(binary digits of 1)(binary digits of 2)...(binary digits of n)...

    http://en.m.wikipedia.org/wiki/Normal_number

  • by a3n on 3/15/15, 1:45 AM

    Disclaimer: I don't know what I'm talking about.

    My dim understanding of the issues leads me to consider a conflict. Pi is more or less considered to be more or less random, or some flavor of random, notwithstanding known patterns of Pi. "Random," to me, sounds a lot like "unorganized."

    A book is definitely organized. A larger book is highly organized (entropically speaking). So while you probably can find the same sequence of words in a two-word or ten-word or other small book in Pi, at some point you get a book that's too highly organized to appear in Pi.

    However, Pi is also infinite, so it's infinitely possible to find any sequence. (This sounds really hand-wavy to me).

    But since Pi is infinite, then isn't it also infinitely unorganized?

  • by danbruc on 3/15/15, 12:59 AM

    Maybe it could be more efficient to go the other way round - instead of searching in the digits of pi kind of invert the BBP formula [1] and try to calculate the position of what you are looking for. But because the BBP formula involves rounding this is certainly not a simple task and I have really no idea if anything could be gained.

    [1] http://en.wikipedia.org/wiki/Bailey%E2%80%93Borwein%E2%80%93...

  • by gchokov on 3/15/15, 10:53 AM

    Theoretically, you can also find all books in a random N-long number as well. Just keep on generating.
  • by antaviana on 3/15/15, 10:25 AM

    At which digit of Pi can I download the code used by the author of the blog post?
  • by hurin on 3/15/15, 2:43 AM

    It's been argued about a lot - with far brighter people unable to come to agreement than the author of this blog.

    The reason the linked article in itself is quite worthless is because it trivializes the question from philosophy of mathematics to oh pi is random let's calculate probability - but obviously that has nothing to do with the real problem.