Metarule CAs

    <p class=default>
      
        Metarule CAs introduce the required openness by postulating a
      
    <br/>

      
        hierarchy of CA rules. Each CA at a particular level in the
      
    <br/>

      
        hierarchy has a finite lattice, a finite number of states and a
      
    <br/>

      
        finite number of rules. However, there are two ways in which
      
    <br/>

      
        metarule CAs extend the standard CA definition:
      
    <br/>

      
        (1) rules at level p are states at level p+1 in the hierarchy,
      
    <br/>

      
        where p ³0.
      
    <br/>

      
        (2) initial conditions are independently specifiable at each
      
    <br/>

      
        level p in the metarule hierarchy.
      
      
        
      
    </p>