| a ∈ ay ↔ (∃ d, ay0, az. ay = ay0 + (a × d)' + az), unique_al(ay), unique_al(ax0), a ∈ ay, ∀ ay0. unique_al(ay0) ∧ (∀ a. a ∈ ax0 ↔ a ∈ ay0) → # ax0 = # ay0, ∀ a0. a0 ∈ ax0 ∨ a0 = a ↔ a0 ∈ ay ⊦ 1 + # ax0 = # ay, a ∈ ax0 |
unique_al(ax0), unique_al(ay0 + (a × d)' + az), ∀ ay0. unique_al(ay0) ∧ (∀ a. a ∈ ax0 ↔ a ∈ ay0) → # ax0 = # ay0, ∀ a0. a0 ∈ ax0 ∨ a0 = a ↔ a0 ∈ az ∨ a0 = a ∨ a0 ∈ ay0 ⊦ # ax0 = # ay0 + # az, a ∈ ax0, a ∈ az
Used simplifier rules: inapp: ⊦ a ∈ ax + ay ↔ ¬ ¬(a ∈ ax ∨ a ∈ ay);%inone: ⊦ a ∈ (b × d0)' ↔ a = b;%nuni-01: ⊦ unique_al(ay + (a × d)' + az) → ¬ a ∈ az;% ⊦ p ∈ p0 ' ↔ p = p0;% ⊦ p ∈ ax + ax0 ↔ ¬ ¬(p ∈ ax ∨ p ∈ ax0);% ⊦ m + n = m + n0 ↔ n = n0;% ⊦ m + n = n + m;% ⊦ (m + n0) + n1 = m + n0 + n1;% ⊦ n + 0 = n;% ⊦ m +1 = m + 1;% ⊦ # p ' = 0 +1;% ⊦ #(ax + ax0) = # ax + # ax0;% ⊦ (ax + ax0) + ax1 = ax + ax0 + ax1;% ⊦ ax = ax0 + p ' + ax1 → p ∈ ax; (forward)