∀ ay, a. (ax0 + ay)[a] = ay[a] ∨ a ∈ ax0 ⊦ ((p + ax0) + ay)[a] = ay[a] ∨ a ∈ p + ax0
Used simplifier rules: assoclist freely generated by [], +;;% ⊦ [] + ax = ax;% ⊦ (ax + ax0) + ax1 = ax + ax0 + ax1;