The First Explicit Projection in the Quantum Blueprint Formalism A Toy Model: Three Distinctions, Two Spacetime Dimensions

This paper computes the first explicit projection in the Quantum Blueprint Formalism. The pre-coherent space is Mₛ = [0,1]³ with three binary distinctions and incompatibilities ω₁₂ = 1.0, ω₁₃ = 0.8, ω₂₃ = 0.6. The background metric g₀ = δᵢⱼ is flat Riemannian (from the Structural Choice). The tension functional Φ = Σ ω²χ(σᵢ)χ(σⱼ) determines the potential. The symplectic form ωI encodes the incompatibility structure. The Witten Laplacian Hw = −Dₛ Δ + Veff is diagonalized numerically on a 40³ grid (Dₛ = 0.1). Its spectrum is strictly positive (λ₀ = 0.79, λ₁ = 1.65, λ₂ = 1.65, λ₃ = 1.66, …) despite the raw Hessian of Φ being indefinite at the pointer state (eigenvalues −1.05, −0.32, +1.37). The spectral gap between the first three excited modes (quasi-degenerate at ω ≈ 0.93) and the fourth mode (ω ≈ 1.31) selects a natural projection dimension. The projection π₀: ℝ³ → ℝ² is constructed as the restriction to the two lowest excited Witten eigenmodes. It is an explicit 2×3 matrix. The induced Riemannian metric on the target MΘ has eigenvalues 0.49, 1.52 (positive definite). The circulation field Ωₛ, projected onto MΘ, identifies the temporal direction. The signature flip Riemannian → Lorentzian produces g_phys = diag(−0.49, +1.52). The emergent speed of light is c = |Ωₛ|/√Dₛ. This demonstrates, for the first time in the QBF corpus, the complete chain: Mₛ (Riemannian, 3D) → Witten spectrum → spectral gap → projection → induced metric → signature change → MΘ (Lorentzian, 2D). The toy model is 3 → 2 dimensions rather than ∞ → 4, but every structural step is identical to the full theory.