80 intro q heq 81 apply phi_irrational 82 exact Set.mem_range.mpr ⟨q, heq⟩ 83 84/-- **THEOREM IC-002.6**: The golden ratio satisfies an irreducible quadratic. 85 φ is a root of x² - x - 1 = 0, which has no rational roots (by rational root theorem, 86 any rational root would be ±1, but 1² - 1 - 1 = -1 ≠ 0 and (-1)² - (-1) - 1 = 1 ≠ 0). -/
depends on (12)
Lean names referenced from this declaration's body.