n = m + 1 ⊦ rtc(n, Pelem)(a, b) ↔ (∃ c. rtc(m, Pelem)(a, c) ∧ Pelem(c, b)), n = 0
Used simplifier rules: n ≠ 0 ⊦ m = n - 1 ↔ n = m + 1; (elim) Used terms: n, m