theorem
proved
term proof
phi_zpow_ne_one
show as:
view Lean formalization →
formal statement (Lean)
49theorem phi_zpow_ne_one {n : ℤ} (hn : n ≠ 0) : PhiForcing.φ ^ n ≠ 1 := by
proof body
Term-mode proof.
50 have hφ_gt := PhiForcing.phi_gt_one
51 intro heq
52 have h0 : PhiForcing.φ ^ (0 : ℤ) = 1 := zpow_zero _
53 have hmono : StrictMono fun m : ℤ => PhiForcing.φ ^ m :=
54 zpow_right_strictMono₀ hφ_gt
55 exact hn (hmono.injective (heq.trans h0.symm))
56