(Page 0501) One may wonder, however, to what extent the behavior one sees depends on the exact scheme that one uses to pick which replacements to apply at each step. The ...

(Page 0516) Space, Time and Relativity Several sections ago I argued that as observers within the universe everything we can observe must at some level be associated purely ...

(Page 0638) abstract terms about the computation that is performed, without necessarily looking at all the details of how it actually works. Why is such an abstraction ...

(Page 0716) But what about processes in nature? Can these also be viewed as computations? Or does the notion of computation somehow apply only to systems with abstract ...

(Page 0897b) Notes for: The World of Simple Programs | Symbolic Systems Properties [of example symbolic system] All initial conditions eventually evolve to expressions of the ...

(Page 0911d) Notes for: Systems Based on Numbers | The Sequence of Primes Perfect numbers Perfect numbers with the property that Apply[Plus, Divisors[n]]==2n have been ...

(Page 0924c) Notes for: Systems Based on Numbers | Partial Differential Equations Implementation [of my PDEs] All the numerical solutions shown were found using the NDSolve ...

(Page 0927c) Notes for: Two Dimensions and Beyond | Cellular Automata Implementation [of 2D cellular automata] An n × n array of white squares with a single black square in ...

(Page 0927d) Notes for: Two Dimensions and Beyond | Cellular Automata General rules [for multidimensional cellular automata] One can specify the neighborhood for any rule in ...

(Page 0939g) Notes for: Two Dimensions and Beyond | Multiway Systems Game systems One can think of positions or configurations in a game as corresponding to nodes in a large ...