Selection Under Constraint - A Structural Derivation from the Persistence Condition

No additional selection mechanism is required. Selection follows necessarily from the persistence condition IR = R/IK ≤ 1. Systems that violate this condition cannot persist as themselves. Systems that satisfy it can. This is not a claim about selection — it is the structural consequence of a condition that any persistent system must satisfy. The central result is the Monotonic Admissibility Theorem: under non-regulation, the set of persistent systems is monotonically non-increasing over time. What is commonly called selection is the population-level projection of this structural boundary. Additionally, three established selection frameworks — biological natural selection, economic market selection, and technological diffusion — reduce to differential persistence within the admissible set. Selection does not operate on systems. It is the boundary that determines which systems continue to exist.