no goals
α : Type u_1
inst✝¹ : DecidableEq α
inst✝ : Fintype α
f✝ g f : Perm α
⊢ card (support f) ≤ 1 ↔ f = 1
rw [le_iff_lt_or_eq, Nat.lt_succ_iff, le_zero_iff, card_support_eq_zero, or_iff_not_imp_right,
  imp_iff_right f.card_support_ne_one]