| ((ls(rxs, xs) * del-list(to_delete, n)))(H), ((del-list(to_delete, n) * ls(rxs, xs)))(H), n < 2, ls(rxs, xs)(H1), n ≤ 1, n ≤ # xs ⊦ r = null, ls(r, a ' + xs)((H1 ++ r)[r, a × rxs]), r ∈ H1 |
⊦ ls(r, a ' + x) = _∃(λ r0. r => a × r0 * ls(r0, x))
((del-list(to_delete, n) * ls(rxs, xs)))(H), ((ls(rxs, xs) * del-list(to_delete, n)))(H), n < 2, ls(rxs, xs)(H1), n ≤ # xs, n ≤ 1 ⊦ r = null, (_∃(λ r0. r => a × r0 * ls(r0, xs)))((H1 ++ r)[r, a × rxs]), r ∈ H1
Used terms: xs, a, r