[comp.ai] Artificial Randomness and Randomness

bwk@mitre-bedford.ARPA (Barry W. Kort) (12/07/88)

In article <EXaLNGy00UgLEARF9n@andrew.cmu.edu> ap1i+@andrew.cmu.edu
(Andrew C. Plotkin) writes:

 > When I flip a coin in my head, I have serious doubts that the
 > results are truly random (based on an amplified quantum randomness).
 > It might just as well be a complex pseudo-random generator.
 >
 > ... If you try to spit out a long string of random bits, the
 > non-randomness of the process becomes painfully clear -- there
 > is a strong correlation between each bit and the several-bit
 > sequence that precedes it.

This is an interesting observation, Andrew.  In Game Theory, there
are some games in which the optimal strategy is to randomize one's
moves.  (Matching pennies and the children's game of Rock, Scissors,
Paper are two that come to mind.)  If my opponent can discover the
assymetry in my not-quite-perfect artificial random move generator,
he can exploit that information to adjust his own counter-moves
and enjoy a winning margin.  The theory may be found under the
name of Nash Equilibrium Solutions to Zero-Sum Games.

--Barry Kort

ap1i+@andrew.cmu.edu (Andrew C. Plotkin) (12/08/88)

bwk@mitre-bedford.ARPA (Barry W. Kort) writes...

/ > When I flip a coin in my head, I have serious doubts that the
/ > results are truly random (based on an amplified quantum randomness).
/ > It might just as well be a complex pseudo-random generator.
/ >
/ > ... If you try to spit out a long string of random bits, the
/ > non-randomness of the process becomes painfully clear -- there
/ > is a strong correlation between each bit and the several-bit
/ > sequence that precedes it.
/
/ This is an interesting observation, Andrew.  In Game Theory, there
/ are some games in which the optimal strategy is to randomize one's
/ moves.  (Matching pennies and the children's game of Rock, Scissors,
/ Paper are two that come to mind.)  If my opponent can discover the
/ assymetry in my not-quite-perfect artificial random move generator,
/ he can exploit that information to adjust his own counter-moves
/ and enjoy a winning margin.

Oh yes. Of course, during those games, both players are trying to second-guess
each other. Even if humans are deterministic machines, that sort of system goes
to chaotic behavior, so cannot be predicted without EXACT knowledge of the
algorithms.

The assymmetry is most marked if you sit at a keyboard or something and say /
type "011011001101101011001010" for a while. Write the predictor program and
check it. Great fun.

--Z