Creation of ballot sequences in a periodic cellular automaton

TL;DR

This paper generalizes a combinatorial proposition to cellular automata with larger cell capacity, introducing a new shift rule that transforms sequences into ballot sequences and reveals particle-like structures.

Contribution

It introduces a novel quasi-cyclic shift rule for cellular automata with multi-capacity cells, enabling transformation into ballot sequences and analysis of particle-like structures.

Findings

Sequences can be transformed into ballot sequences using cyclic and quasi-cyclic shifts.

The new CA rule exhibits traveling kink-like structures similar to particles.

The method aids in solving initial value problems in related cellular automata.

Abstract

Motivated by an attempt to develop a method for solving initial value problems in a class of one dimensional periodic cellular automata (CA) associated with crystal bases and soliton equations, we consider a generalization of a simple proposition in elementary mathematics. The original proposition says that any sequence of letters 1 and 2, having no less 1's than 2's, can be changed into a ballot sequence via cyclic shifts only. We generalize it to treat sequences of cells of common capacity s > 1, each of them containing consecutive 2's (left) and 1's (right), and show that these sequences can be changed into a ballot sequence via two manipulations, cyclic and "quasi-cyclic" shifts. The latter is a new CA rule and we find that various kink-like structures are traveling along the system like particles under the time evolution of this rule.