| unique_al((p0 ' + ax0) + p ' + ay), ∀ p, ay. unique_al(ax0 + p ' + ay) → ax0 + ay = [] ∨ ¬ (ax0 + ay).first.1 ∈ (ax0 + ay).rest ∧ unique_al((ax0 + ay).rest) ⊦ ¬ p0.1 ∈ ax0 ∧ ¬ p0.1 ∈ ay ∧ unique_al(ax0 + ay) |
⊦ unique_al(ay) ↔ ay = [] ∨ ¬ ay.first.1 ∈ ay.rest ∧ unique_al(ay.rest)
(p0 ' + ax0) + p ' + ay = [] ∨ ¬ ((p0 ' + ax0) + p ' + ay).first.1 ∈ ((p0 ' + ax0) + p ' + ay).rest ∧ unique_al(((p0 ' + ax0) + p ' + ay).rest), ∀ p, ay. unique_al(ax0 + p ' + ay) → ax0 + ay = [] ∨ ¬ (ax0 + ay).first.1 ∈ (ax0 + ay).rest ∧ unique_al((ax0 + ay).rest) ⊦ ¬ p0.1 ∈ ax0 ∧ ¬ p0.1 ∈ ay ∧ unique_al(ax0 + ay)
Used terms: (p0 ' + ax0) + p ' + ay