Notes - Pages 223-297

Classification system
1,2,3,4 in order of increasing complex behaviors.
231-232
Class 4
Can be seen as a in between state of classes 2 and 3. Localized structures that become global repetitive patterns in 4. The cellular automata that move are of this class.
238-240
Initial conditions
class 1, any initial condition goes to one final state. Class 2 can have structures that can persist but remain local. Class 3 any change in local state gets spread to the entire structure including init conditions. Class 4 similar to class 3 but only if the conditions effect the moving structure, othewise behaves like clas 2
250-252
Information
How the initial conditions, or information is spread through the automata can put limits on their structures. Class 2 because information is localized, it must lead to repeated patterns. In fact any bounded automata will show repeat patterns. Class 3 can emulate class 2, and show randomness given sufficiently random initial conditions, structured initial conditions lead to structured output. If class 4 has persistent structures it is likely moving ones can be found
254-286

Class System

  1. Simple, any initial condition eventually ends in the same state

  2. Finite set of final states that consists of a set of structure that either repeat every few steps or remain forever

  3. Seemingly random, but structures and patterns are seen throughout

  4. Localized structures that can interact with one another

    This chapter had a lot of information on how cellular automata relates to infromation or structure, much of it images that wont be reproduced here. Many of the properties claimed are not supported by proofs, and the author doesnt define randomness in the way I would, if Class 3 is random then it should not have repeated patterns in it, in my opinion there should be no patterns in randomness.