The Structure of Configurations in One-Dimensional Majority Cellular Automata: From Cell Stability to Configuration Periodicity

TL;DR

This paper analyzes the structure and periodicity of configurations in one-dimensional majority cellular automata with cyclical boundaries, revealing that most configurations have a specific periodic form with bounded sequence lengths, and extends results to the minority rule.

Contribution

It introduces the notion of cell stability to characterize configuration structures and proves that non-fixed-point configurations have a bounded, periodic form in majority automata.

Findings

Configurations are either fixed points or 2-cycles with a specific periodic structure.

Non-fixed-point configurations have a form with sequences of cells of length at most r.

Results extend to the minority rule, showing similar structural properties.

Abstract

We study the dynamics of (synchronous) one-dimensional cellular automata with cyclical boundary conditions that evolve according to the majority rule with radius $ r $. We introduce a notion that we term cell stability with which we express the structure of the possible configurations that could emerge in this setting. Our main finding is that apart from the configurations of the form $ (0^{r+1}0^* + 1^{r+1}1^*)^* $, which are always fixed-points, the other configurations that the automata could possibly converge to, which are known to be either fixed-points or 2-cycles, have a particular spatially periodic structure. Namely, each of these configurations is of the form $ s^* $ where $ s $ consists of $ O(r^2) $ consecutive sequences of cells with the same state, each such sequence is of length at most $ r $, and the total length of $ s $ is $ O(r^2) $ as well. We show that an analogous result also holds for the minority rule.