| # x1 = # rx1, # x0 = # rx0 ⊦ x0 = [], x1 = [], dls(head, prev, x0 + a ' + x1, rx0 + r ' + rx1, next, tail) = _∃(λ r0, r1. dls(head, prev, x0, rx0, r, r0) * r => mkcell(r0, r1, a) * dls(r1, r, x1, rx1, next, tail)) |
⊦ P0 = P1 ↔ (∀ P, H. ((P0 * P))(H) ↔ ((P1 * P))(H))
[Concretesimprules(()), Extraterms((_∃ (λ r0, r1. dls(head, prev, x0, rx0, r, r0) * r => mkcell(r0, r1, a) * dls(r1, r, x1, rx1, next, tail)) dls (head, prev, x0 + a ' + x1, rx0 + r ' + rx1, next, tail)))]