{ "id": "2205.15402", "version": "v1", "published": "2022-05-30T19:59:55.000Z", "updated": "2022-05-30T19:59:55.000Z", "title": "A generalization of cellular automata over groups", "authors": [ "A. Castillo-Ramirez", "M. Sanchez-Alvarez", "A. Vazquez-Aceves", "A. Zaldivar-Corichi" ], "comment": "11 pages", "categories": [ "math.GR", "cs.FL" ], "abstract": "Let $G$ be a group and let $A$ be a finite set with at least two elements. A cellular automaton (CA) over $A^G$ is a function $\\tau : A^G \\to A^G$ defined via a finite memory set $S \\subseteq G$ and a local function $\\mu :A^S \\to A$. The goal of this paper is to introduce the definition of a generalized cellular automaton (GCA) $\\tau : A^G \\to A^H$, where $H$ is another arbitrary group, via a group homomorphism $\\phi : H \\to G$. Our definition preserves the essence of CA, as we prove analogous versions of three key results in the theory of CA: a generalized Curtis-Hedlund Theorem for GCA, a Theorem of Composition for GCA, and a Theorem of Invertibility for GCA. When $G=H$, we prove that the group of invertible GCA over $A^G$ is isomorphic to a semidirect product of $\\text{Aut}(G)^{op}$ and the group of invertible CA. Finally, we apply our results to study automorphisms of the monoid $\\text{CA}(G;A)$ consisting of all CA over $A^G$. In particular, we show that every $\\phi \\in \\text{Aut}(G)$ defines an automorphism of $\\text{CA}(G;A)$ via conjugation by the invertible GCA defined by $\\phi$, and that, when $G$ is abelian, $\\text{Aut}(G)$ is embedded in the outer automorphism group of $\\text{CA}(G;A)$.", "revisions": [ { "version": "v1", "updated": "2022-05-30T19:59:55.000Z" } ], "analyses": { "subjects": [ "37B15", "68Q80" ], "keywords": [ "generalization", "invertible gca", "outer automorphism group", "finite memory set", "local function" ], "note": { "typesetting": "TeX", "pages": 11, "language": "en", "license": "arXiv", "status": "editable" } } }