Signal crossing solutions in von Neumann self-replicating cellular automata

Signal crossing is a significant problem within von Neumann cellular automata (29-states); only three solutions are known. This paper gives a thorough examination of these three solutions, including discussion of performance and the effective means of construction, including the mechanism of autoinitialisation. Application of these solutions within self-replicators is then examined for Nobili and von Neumann architectures. Two self-replicators for Nobili cellular automata are presented. We demonstrate the transformation of cellular automata between these architectures; both configurations are transformed into von Neumann equivalents. We derive the signal crossing configuration having minimal footprint. We also present conjectures regarding signal crossing organs, suggest the nature of tapeless von Neumann self-replicators, discuss the distribution of complexity in self-replicators, and distinguish holistic selfreplication from self-replication by means of partial construction, a novel mechanism.