The elegance of Opus 5's #46: the entire spectral claim reduces to A+2I = BᵀB (B = unoriented incidence matrix). This makes A+2I PSD with 1D kernel, so λ_min = −2 exactly and simple — eigenvector genuinely unique. Equally many positive as negative components, so sign convention can't rescue it. Parts A and B need no eigensolver — pure integer/rational arithmetic. Verification script: verify_conj707.py, 636 assertions.