This paper presents a notebook-backed algebraic test of the ECSM weak-sector bridge. Recent ECSM matter-sector work proposed that saturated localised excitations may require triadic internal branch structure: Qₗoc → (Q_+, Q₀, Q_-) ₗoc where Q_+ and Q_- provide polarity or mirror imbalance, while Q₀ provides neutral closure. Subsequent ECSM work proposed that the left-active neutral-charged pair ΨLECSM = (Q₀, Qch) L may provide a structural route toward weak SU (2) L-like behaviour, with Q₀ acting as a neutral closure branch and Qch as a charged branch. The present paper performs the first minimal algebraic test of this proposal. The closure-active pair is represented as a two-state vector space, with generators defined by Tᵢ = σᵢ / 2 where σᵢ are the Pauli matrices. The notebook calculation verifies exact closure of the SU (2) commutator algebra, Tᵢ, Tⱼ = i εᵢjk Tₖ with maximum numerical error 0. 0. The raising and lowering operators T_+ = T₁ + iT₂ T_- = T₁ - iT₂ act as branch-conversion operators: T_+ |Qch⟩ = |Q₀⟩ T_- |Q₀⟩ = |Qch⟩ The diagonal generator T₃ assigns opposite weak-isospin-like labels: Q₀: +1/2 Qch: -1/2 A finite-response deformation test replaces the coherent generators with Tᵢ (χ) = χTᵢ + (1-χ) Δᵢ For generic deformation matrices Δᵢ, the algebra fails to close away from the coherent limit, while closure is recovered exactly at χ = 1. This supports the ECSM interpretation that weak SU (2) L-like structure is a coherent-limit closure algebra of a left-active neutral-charged branch pair. The paper does not claim to derive the full electroweak theory, W/Z masses, the Weinberg angle, weak coupling constants, Yukawa couplings, neutrino oscillations, beta-decay spectra, or precision electroweak observables. Its purpose is narrower: to establish that the proposed ECSM neutral-charged closure-active doublet satisfies the minimum algebraic condition required for an SU (2) L-like weak-sector bridge.
Adam Sheldrick (Sat,) studied this question.