| # ax0 = # ay0 + # az, unique_al(ay0 + (a × d)' + az), unique_al(ax0), ∀ ay0, b0. # ax0 = # ay0 ∧ unique_al(ay0) ∧ b0 ∈ ay0 ∧ (∀ a. a ∈ ax0 → a ∈ ay0) → b0 ∈ ax0, ∀ a0. a0 ∈ ax0 → a0 ∈ ay0 ∨ a0 ∈ az, b ∈ ay0 ∨ b ∈ az ⊦ b = a, b ∈ ax0, a ∈ ax0, a ∈ ay0, a ∈ az |
# ax0 = # ay0 + # az, unique_al(ax0), unique_al(ay0 + (a × d)' + az), # ax0 = #(ay0 + az) ∧ unique_al(ay0 + az) ∧ b ∈ ay0 + az ∧ (∀ a. a ∈ ax0 → a ∈ ay0 + az) → b ∈ ax0, ∀ a0. a0 ∈ ax0 → a0 ∈ ay0 ∨ a0 ∈ az, b ∈ ay0 ∨ b ∈ az ⊦ b = a, a ∈ az, a ∈ ay0, a ∈ ax0, b ∈ ax0
Used terms: ay0 + az, b