# Chrystopher Nehaniv > **Machine-Evolution Nexus:** [[articles/Digital Darwinism and the Invisible World of Machine Evolution|Digital Darwinism and the Invisible World of Machine Evolution]] places this node within the history and governance of substrate-independent evolution. **Domain:** Artificial Life / Mathematics **Doc Type:** Canonical Wiki Node **Maturity:** Developed ## Definition Chrystopher L. Nehaniv is a mathematician and artificial-life researcher whose work includes self-reproduction, information and evolutionary systems. ## Nexus Context With Hiroki Sayama he authored the twenty-five-year Evoloops retrospective, clarifying competing definitions of replication and reproduction and surveying renewed work on open-ended evolution. ## Evidence Boundary The review distinguishes criteria rather than imposing a single loose definition; wiki claims should preserve those differences. ## Relationships [[wiki/Hiroki Sayama|Hiroki Sayama]], [[wiki/Evoloop|Evoloop]], [[wiki/Self-Replication|Self-Replication]], [[wiki/Open-Ended Evolution|Open-Ended Evolution]] ## Sources / Provenance - Sayama and Nehaniv, “Self-Reproduction and Evolution in Cellular Automata” (2025).