An Intrinsically Universal Family of Causal Graph Dynamics
Résumé
Causal Graph Dynamics generalize Cellular Automata, extending them to bounded degree, time varying graphs. The dynamics rewrites the graph in discrete time-steps, with respect to two physics-like symmetries: causality (there exists a bounded speed of information prop- agation) and shift-invariance (the rewriting acts everywhere the same). Intrinsic universality is the ability of the instance of a model to simulate all other instances, while preserving the structure of the computation. We present here an intrinsically universal family of Causal Graph Dynamics, and give insight on why it seems impossible to improve this result to the existence of a unique intrinsically universal instance.