| ⊦ (∀ ay, a. (ax0 + ay)[a] = ay[a] ∨ a ∈ ax0) → (((a × d)' + ax0) + ay)[a0] = ay[a0] ∨ a0 ∈ (a × d)' ∨ a0 ∈ ax0 |
∀ ay, a. (ax0 + ay)[a] = ay[a] ∨ a ∈ ax0 ⊦ a0 = a, (ax0 + ay)[a0] = ay[a0], a0 ∈ ax0
Used simplifier rules: inone: ⊦ a ∈ (b × d0)' ↔ a = b;%assoc-no: ⊦ a ≠ b → ((b × d)' + ax)[a] = ax[a];% ⊦ (ax + ax0) + ax1 = ax + ax0 + ax1;