| a × d ∈ ay ∧ perm(ax0, ay -1l (a × d)), perm(ay, (a × d)' + ax0), unique_al(ax0), ∀ ay0. perm(ay0, ax0) ∧ perm(ax0, ay0) → unique_al(ay0) ⊦ a ∈ ax0, unique_al(ay) |
perm(ax0, ay -1l (a × d)), a × d ∈ ay, perm(ay, (a × d)' + ax0), unique_al(ax0), perm(ay -1l (a × d), ax0), ∀ ay0. perm(ay0, ax0) ∧ perm(ax0, ay0) → unique_al(ay0) ⊦ a ∈ ax0, unique_al(ay)
Used simplifier rules: ⊦ perm(ax, ax);% ⊦ perm(ax, ax0) ∧ perm(ax0, ax1) → perm(ax, ax1); (forward)% ⊦ perm(ax, ax0) → perm(ax0, ax); (forward)