axiom U : Typeaxiom Ax1 : ∀ (b : U) (a : U), b = aaxiom Ax2 : ∀ (b : U) (c : U), b = caxiom Hyp1 : ∀ (a : U) (c : U), a = ctheorem SL1 : ∀ (a : U) (c : U), a = c := by intro a c have h := Ax2 a c conv at h => lhs; simp only [Ax1] exact htheorem FinalGoal : ∀ (a : U) (c : U), a = c := by intro a c exact SL1 a c