| ((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 |
((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, r ∈ H1, ∃ r0. ((r => a × r0 * ls(r0, xs)))((H1 ++ r)[r, a × rxs])
Used simplifier rules: ⊦ (_∃ rP)(H) ↔ (∃ r. rP(r)(H)); (s)