| 0 ≤ i, ∀ j0, i. i→n(j0) < i→n(0) → 0 ≤ i ∧ 0 ≤ j0 → fac(i + j0) = fac(i) * Π countFun(1, j0, λ j0. i + j0) ⊦ Π countFun(1, 0, λ j0. i + j0) = 1 |
⊦ j < i → countFun(i, j, intfun) = []
Used simplifier rules: prod-empty: ⊦ Π [] = 1; from specification intlist Used terms: λ j0. i + j0, 0, 1