Environment-Level Screening of Threshold-Conditioned Lithium Transport Under a Necessary Viability Filter

Environment-Level Screening of Threshold-Conditioned Lithium Transport Under a Necessary Viability Filter applies the lithium‑viability framework developed in Threshold-Conditioned Lithium Depletion in Recurrence-Amplified Transport Domains: A Filter Theorem and Viability Framework (Partin, 2026; DOI: 10.5281/zenodo.21314964) to a set of astrophysical and cosmological environments. The paper does not construct a physical model of recurrence‑amplified lithium depletion; instead, it performs a symbolic, necessary‑condition screening to determine which environments remain eligible for further analysis once structural admissibility, threshold access, recurrence‑adjusted burden feasibility, and observational non‑exclusion are imposed. Candidate environments—including primordial Big Bang nucleosynthesis plasma, shock‑confined early‑universe pockets, curvature‑driven confinement domains, compact stellar remnants and stellar shells, and chemically active high‑redshift systems—are evaluated using the imported viability gates. Each environment is assigned one of four classifications: Excluded, Undetermined, Conditionally Viable, or Viable Under Filter. No environment reaches full viability under the necessary‑condition filter, but curvature‑driven confinement domains and compact stellar remnant or shell environments emerge as Conditionally Viable due to their alignment with recurrence‑compatible confinement and threshold‑sampling architecture. This paper provides the environment‑level screening component of the lithium‑transport program, narrowing the search space for recurrence‑amplified threshold transport without modifying standard nuclear physics or ΛCDM cosmology and without asserting that lithium depletion occurs in any candidate domain.