Theorem: MyGroup.inv_inv (IIScExperiments/Solutions/GroupTheorySolutions.lean)

State before:
G : Type
inst✝ : MyGroup G
a b c : G
⊢ a⁻¹⁻¹ = a
Tactic:
simp [← mul_eq_one_iff_eq_inv]
State after:
no goals