S : Type u_1
inst✝ : Semigroup S
a b x y z x' y' : S
ha : SemiconjBy a y z
hb : SemiconjBy b x y
⊢ a * b * x = z * (a * b)
S : Type u_1
inst✝ : Semigroup S
a b x y z x' y' : S
ha : SemiconjBy a y z
hb : SemiconjBy b x y
⊢ SemiconjBy (a * b) x z
unfold SemiconjBy
no goals
S : Type u_1
inst✝ : Semigroup S
a b x y z x' y' : S
ha : SemiconjBy a y z
hb : SemiconjBy b x y
⊢ a * b * x = z * (a * b)
rw [mul_assoc, hb.eq, ←mul_assoc, ha.eq, mul_assoc]