| (r ' + x1)[m] = (r ' + x1)[n], path(r ' + x1, H), n ≤ # x1, m < n, m < # x1 ⊦ m = n, x1 = [], ∃ m, n, r0. m < n ∧ reachable-n(H, m, r, r0) ∧ reachable-n(H, n, r, r0) |
(r ' + x1)[m] = (r ' + x1)[n], n < m, path(r ' + x1, H), m ≤ # x1, n < # x1 ⊦ m = n, x1 = [], ∃ m, n, r0. m < n ∧ reachable-n(H, m, r, r0) ∧ reachable-n(H, n, r, r0)
[[CONCRETESIMPRULES : ()]]