theorem
proved
term proof
phi_irrational
show as:
view Lean formalization →
formal statement (Lean)
61theorem phi_irrational : Irrational phi := by
proof body
Term-mode proof.
62 -- Our phi equals Mathlib's goldenRatio
63 have h_eq : phi = Real.goldenRatio := rfl
64 rw [h_eq]
65 exact Real.goldenRatio_irrational
66
67/-! ### φ power bounds -/
68
69/-- Key identity: φ² = φ + 1 (from the defining equation x² - x - 1 = 0). -/