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

State before:
G : Type
inst✝ : MyGroup G
a✝ b c a : G
⊢ a * 1 = a
Tactic:
apply mul_eq_of_eq_inv_mul
State after:
case h
G : Type
inst✝ : MyGroup G
a✝ b c a : G
⊢ 1 = a⁻¹ * a

State before:
case h
G : Type
inst✝ : MyGroup G
a✝ b c a : G
⊢ 1 = a⁻¹ * a
Tactic:
rw [inv_mul_self]
State after:
no goals