This paper is the second part of a series of two papers dealing with bulking: a way to define quasi-order on cellular automata by comparing space-time diagrams up to rescaling. In the present paper,â€¦ (More)

We investigate the decidability of the periodicity and the immortality problems in three models of reversible computation: reversible counter machines, reversible Turing machines and reversibleâ€¦ (More)

Motivated by the study of cellular automata algorithmic and dynamics, we investigate an extension of ultimately periodic words to two-dimensional infinite words: collisions. A natural compositionâ€¦ (More)

In this note, colorings of the plane by finite sequential machines are compared to previously introduced notions of ultimately periodic tilings of the plane. Finite automata with no counterâ€¦ (More)

We define a new transfinite time model of computation, infinite time cellular automata. The model is shown to be as powerful than infinite time Turing machines, both on finite and infinite inputs;â€¦ (More)

We prove that given a set X of two nonempty words, a set Y of nonempty words commutes with X if and only if either Y is a union of powers of X or X; Y t + for some primitive word t. We also show thatâ€¦ (More)