CDR: RE: Think cash

[Sampo A Syreeni]

On Wed, 11 Oct 2000, Trei, Peter wrote:

>by a computer are the killers. Any problem which one computer 
>can create, and solve, can also be solved by another.

Not true. One example from the theory of computation: given a finite set of
3x3 matrices, determine whether some finite matrix product of them equals
zero (i.e. repetition and reordering is allowed). This is a noncomputable
problem, even when we know that all such series can be computer generated
and a given solution can be easily verified. Sort of cracked me when I first
found it.

Naturally this particular problem isn't suitable for human consumption, like
the original mail required.

Sampo Syreeni <decoy at iki.fi>, aka decoy, student/math/Helsinki university