## Semitotalistic rules

A slight generalization of totalistic rules is to make the transition depend explicitly upon the state of the central cell, but otherwise only on the state sum of the remaining cells; the combination is called a semitotalistic rule. Neighborhoods of even length do not have a central cell, so the concept may be extended still further to include partitioning the cells into two groups, then using the pair of state sums to define the transition.

The placement of the semitotalistic rule follows the same general principles as that of the totalistic rule, the same also to be said about the variety of options.

Harold V. McIntosh

E-mail:mcintosh@servidor.unam.mx