Name | Golden-Ratio Cycle Eigenvalue
Object | $2\cos(2\pi/5)$
Type | Exact trigonometric identity on $C_5$
Identity | $2\cos(2\pi/5)=(\sqrt{5}-1)/2$
Evidence | E0 + E1
Boundary | C_5 adjacency spectrum only. Distinct from Civic 163 (golden-ratio Newton lock) and from RUB5-C02 (C_5^3 Kronecker Laplacian).
Parents: FPV20-C01, FPV20-C06.
Witness: PF-FPV20-GRAPH-011 · residual $0$.