random

[Mark 'Kamikaze' Hughes]

Sat, 2 Jun 2001 17:28:22 +0200 in <9fb0ju01a8a at enews2.newsguy.com>,
Alex Martelli <aleaxit at yahoo.com> spake:
> "David C. Ullrich" <ullrich at math.okstate.edu> wrote in message
> news:3b18ea18.332276 at nntp.sprynet.com...
>> Probably "is in a state of sin" is not well-defined.
> Presumably was meant as a humorous quip?

  IIRC, JVN wrote that in a paper on arithmetic methods of generating
pseudo-random numbers, so the word you're grasping for is "ironic". 

>> I take the comment to mean that there is no "percect"
>> arithmetical RNG. It seems extremely clear to me that
>> there isn't, and I haven't heard anything that explains
>> how Chaitin's work _does_ show that there exists
>> a perfect arithemtical RNG.
> I'm not sure what you mean by "perfect" (or "percect" --
> not sure if that was a typo, and if so, whether it was for
> 'percept' or 'perfect').  If you mean one requiring an
> infinite amount of information for prediction,

  A true random number generator is not one that requires an infinite
amount of information to predict, it is one that is *impossible* to
predict, regardless of how much information you have.

  Anything else is a pale substitute.  You can have pseudo-random
algorithms with varying degrees of randomness, but they are ultimately
predictable.

  Now, if Chaitin's come up with a better PRNG, that's fine work, and
could be very useful.  But he's still "in a state of sin", because it
isn't truly random.

> Meanwhile I still see nothing 'sinful' in dealing with
> randomness finitely,

  It's simple.  If you have a pseudo-random number generator, you will
eventually repeat, and other people, given the right information, can
duplicate your random numbers.  This is, to put it mildly, not a good
thing (the word "catastrophic" comes to mind in crypto applications).

-- 
 <a href="http://kuoi.asui.uidaho.edu/~kamikaze/"> Mark Hughes </a>
"I will tell you things that will make you laugh and uncomfortable and really
fucking angry and that no one else is telling you.  What I won't do is bullshit
you.  I'm here for the same thing you are.  The Truth." -Transmetropolitan #39