Dear Wei, Georges, et al, Where does the notion of computational resources factor in this?
Stephen ----- Original Message ----- From: "Wei Dai" <[EMAIL PROTECTED]> To: "Georges Quenot" <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]> Sent: Monday, January 12, 2004 8:50 PM Subject: Re: Is the universe computable? > On Tue, Jan 06, 2004 at 05:32:05PM +0100, Georges Quenot wrote: > > Many other way of simulating the universe could be considered like > > for instance a 4D mesh (if we simplify by considering only general > > relativity; there is no reason for the approach not being possible in > > an even more general way) representing a universe taken as a whole > > in its spatio-temporal aspect. The mesh would be refined at each > > iteration. The relation between the time in the computer and the time > > in the universe would not be a synchrony but a refinement of the > > resolution of the time (and space) in the simulated universe as the > > time in the computer increases. > > > > Alternatively (though both views are not necessarily exclusive), one > > could use a variational formulation instead of a partial derivative > > formulation in order to describe/build the universe leading again to > > a construction in which the time in the computer is not related at > > all to the time in the simulated universe. > > Do you have references for these two ideas? I'm wondering, suppose the > universe you're trying to simulate contains a computer that is running a > factoring algorithm on a large number, in order to cryptanalyze somebody's > RSA public key. How could you possibly simulate this universe without > starting from the beginning and working forward in time? Whatever > simulation method you use, if somebody was watching the simulation run, > they'd see the input to the factoring algorithm appear before the output, > right? > >