| j ≤ i, 0 < j, 0 < i ⊦ j | binom_coef(i, j - 1) * (i + 1 - j) |
⊦ 0 < j ∧ j ≤ i → binom_coef(i, j) * j = binom_coef(i, j - 1) * (i + 1 - j)
Used simplifier rules: div-mult: ⊦ i | i * j; from specification int-gcd%associativity: ⊦ i * j * j0 = (i * j) * j0; from specification int-mult%commutativity: ⊦ i * j = j * i; from specification int-mult Used terms: j, i