| n = n0 +1, reachable-1(H, r, r1), reachable-1(H, r1, r2), reachable-n(H, n, r2, r0), ∀ H0, r1, r2. (∃ r3. reachable-1(H0, r1, r3) ∧ reachable-n(H0, n, r3, r2)) ↔ (∃ x. path(x, H0) ∧ hd x = r1 ∧ x.last = r2 ∧ # x = 2 + n) ⊦ ∃ x. path(x, H) ∧ hd x = r ∧ x.last = r0 ∧ # x = 3 + n |
reachable-1(H, r, r1), reachable-1(H, r1, r2), reachable-1(H, r2, r3), reachable-n(H, n0, r3, r0), ∀ H0, r4, r5. (∃ r6. reachable-1(H0, r4, r6) ∧ (∃ r1. reachable-1(H0, r6, r1) ∧ reachable-n(H0, n0, r1, r5))) ↔ (∃ x. path(x, H0) ∧ hd x = r4 ∧ x.last = r5 ∧ # x = 3 + n0) ⊦ ∃ x. path(x, H) ∧ hd x = r ∧ x.last = r0 ∧ # x = 4 + n0
Used simplifier rules: reachable-n-rec: ⊦ reachable-n(H, n + 1, r, r0) ↔ (∃ r1. reachable-1(H, r, r1) ∧ reachable-n(H, n, r1, r0));%c: ⊦ m + n = n + m; from specification nat-basic2%a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic2%succ: ⊦ m +1 = m + 1; from specification nat-basic2