A theorem‑level derivation of the cosmological constant Λ is presented within the BRane Interface Substrate Model (BRISM). Using only the axioms of phase neutrality, positivity, σ‑additivity, norm conservation, and Naimark–Stinespring two‑sided dilation, BRISM fixes a minimal interface scale ε = 1/π² and a unique additive π‑structureX = 4π³ + π² + π. The local Casimir theorem shows that interface deformation is governed by the geometric factor (π²) /240 arising from a 24×10 bulk–brane channel structure. Generalizing this to the global interface, BRISM identifies 30 independent projection channels (12 transverse + 12 dual‑transverse + 6 geometric), each contributing a multiplicative suppression factor ε/X. Combined with the holographic reduction (L⁻⁴ → L⁻²), the global interface suppression reaches 10⁻¹²⁰ without invoking vacuum energy, renormalization, or dynamical fields. The residual tension is defined on the cosmic S²‑interface of area Acosmic ≈ 10⁵² m², yielding a curvature contribution ΛBRISM = 10⁻¹²⁰ × Acosmic⁻¹ = 10⁻⁵² m⁻², in excellent agreement with observations. The result identifies Λ not as vacuum energy, but as a holographic interface tension fixed entirely by the invariant BRISM geometry. This provides a structural resolution of the 10¹²⁰ discrepancy and establishes Λ as the global analogue of the BRISM–Casimir effect. A structured consistency analysis of the underlying BRISM interface framework is provided in the accompanying Supplement (DOI: 10. 5281/zenodo. 19296467) and conceptual overview (DOI: 10. 5281/zenodo. 18848511). All BRISM papers on Zenodo >> Searchlist
Swen Carlo Heinze (Mon,) studied this question.