I havenít read much about invertible systems. Curiously though, earlier this year I was working on a difficult problem related to optimistic concurrency control in a distributed object oriented database Iím developing, and found that I only solved it when I decomposed it as an invertible problem into parts that were invertible. The decomposition always involved invertible functions with two inputs and two outputs. All state changes (to a local database) are applied as invertible operations, and the problem is to transform operations so they can be applied in different orders at different sites and yet achieve convergence. I guess itís unlikely that this has relevance to physics.
- David -----Original Message----- From: Stephen Paul King [mailto:[EMAIL PROTECTED] Sent: Thursday, 13 November 2003 10:14 AM To: [EMAIL PROTECTED] Subject: Re: Reversible computing Dear David, † ††† Have you read any of the books by Michael C. Mackey on the implications of reversible (invertible) and non-invertible systems? Some, notably Oliver Penrose, have attacked his reasoning, but I find his work to be both insightful and novel and that his detractors are mostly driven by their own inabilities to take statistical dynamics and thermodynamics forward. † ††† Mackey shows that invertible dynamical system will be at equilibrium perpetually and that only non-invertible system will exhibit an "arrow of time". I am very interested in the subject of reversible computation, as it relates to my study of Hitoshi Kitada's theory of Time,†and would like to†learn about†what you have found about them. † Kindest regards, † Stephen ----- Original Message ----- From: David Barrett-Lennard To: [EMAIL PROTECTED] Sent: Wednesday, November 12, 2003 8:36 PM Subject: Reversible computing I have been wondering whether there is something significant in the fact that our laws of physics are mostly time symmetric, and we have a law of conservation of mass/energy. Does this suggest that our universe is associated with a reversible (and information preserving) computation? - David