| Pelem(c, b), rtc(m0 +1, Pelem)(a, c), ∀ Pelem, c, b, a. Pelem(c, b) ∧ rtc(m0, Pelem)(a, c) → (∃ c. Pelem(a, c) ∧ rtc(m0, Pelem)(c, b)) ⊦ ∃ c. Pelem(a, c) ∧ rtc(m0 +1, Pelem)(c, b) |
Pelem(c, b), Pelem(a, c0), rtc(m0, Pelem)(c0, c), ∀ Pelem, c, b, a. Pelem(c, b) ∧ rtc(m0, Pelem)(a, c) → (∃ c. Pelem(a, c) ∧ rtc(m0, Pelem)(c, b)) ⊦ ∃ c1. Pelem(a, c1) ∧ (∃ c. Pelem(c1, c) ∧ rtc(m0, Pelem)(c, b))
Used simplifier rules: rtc-rec: ⊦ rtc(n + 1, Pelem)(a, b) ↔ (∃ c. Pelem(a, c) ∧ rtc(n, Pelem)(c, b));%c: ⊦ m + n = n + m; from specification nat-basic%a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic% ⊦ m +1 = m + 1; (s)