B0 — Relative Causal Closure Theorem

Introduces B0, a theorem establishing necessary and sufficient conditions for causal describability via relative causal closure in irreversible systems. This paper introduces B0 — the Relative Causal Closure Theorem, establishing a necessary and sufficient condition for causal describability of persistence in irreversible systems. Persistence is causally describable from a reference frame if and only if that frame contains at least one internally accessible compensatory causal loop. When such closure is lost, persistence may remain real while becoming causally indescribable.