We consider the family of all the Cellular Automata (CA) sharing the same local rule but having different memories. This family contains also all CA with memory (one-sided CA) which can act both on and on . We study several set theoretical and topological properties for these classes. In particular, we investigate whether the properties of a given CA are preserved when considering the CA obtained by changing the memory of the original one (shifting operation). Furthermore, we focus our attention on the one-sided CA acting on , starting from the one-sided CA acting on and having the same local rule (lifting operation). As a particular consequence of these investigations, we prove that the long-standing conjecture [Surjectivity Dense Periodic Orbits (DPO)] can be restated in several different (but equivalent) ways. Furthermore, we give some results on properties conserved under the iteration of the CA global map.
A short version of this paper has been presented at CiE 2007 Conference [L. Acerbi, A. Dennunzio, E. Formenti. Shifting and lifting of cellular automata. in: Third Conference on Computability in Europe, CiE 2007, in: Lecture Notes in Computer Science, vol. 4497, Springer Verlag, 2007, pp. 1–10].