| 0 ≤ j - 1 ∧ j - 1 ≤ i - 1, 0 ≤ j ∧ j ≤ i, j ≤ i, 0 < j, 0 < i ⊦ i * fac(i - 1) / (fac(i - 1 - (j - 1)) * fac(j - 1)) = j * fac(i) / (fac(i - j) * fac(j)) |
0 < i, 0 < j, j ≤ i, 0 ≤ j, 0 ≤ i ⊦ i * fac(i - 1) / (fac(i - j) * fac(j - 1)) = j * fac(i) / (fac(i - j) * fac(j))
Used simplifier rules: forward-le-01: ⊦ i ≤ j ∧ 0 ≤ i → 0 ≤ j; (forward) from specification int-abs%sub-le: ⊦ i - j ≤ i0 ↔ i ≤ j + i0; from specification int-abs%leone: ⊦ 1 ≤ i ↔ 0 < i; from specification int-abs%sub-le-01: ⊦ i ≤ j - i0 ↔ i + i0 ≤ j; from specification int-abs%add-c: ⊦ i + j = j + i; from specification int-basic2%add-a: ⊦ i + j + i0 = (i + j) + i0; from specification int-basic2%Sub-def: ⊦ i + (j - i) = j; from specification int-abs%sub-sub: ⊦ i - j - i0 = i - j + i0; from specification int-abs