| ∀ i1, i2, j, j0. i→n(i1) + i→n(i2) < i→n(i) + i→n(0 * 10) → true → mkDecimal(i1, j) * mkDecimal(i2, j0) = mkDecimal(i1 * i2, abs(j) + abs(j0)) ⊦ j0 = 0, abs(j) + abs(j0) = 0, mkDecimal(mkDecimal(i, j).int * mkDecimal(0, abs(j0) - 1).int, mkDecimal(i, j).scale + mkDecimal(0, abs(j0) - 1).scale) = mkDecimal(0, abs(j) + abs(j0) - 1), i % 10 = 0 ∧ j ≠ 0 |
∀ i1, i2, j, j0. i→n(i1) + i→n(i2) < i→n(i) + i→n(0 * 10) → true → mkDecimal(i1, j) * mkDecimal(i2, j0) = mkDecimal(i1 * i2, abs(j) + abs(j0)) ⊦ j0 = 0, abs(j) + abs(j0) = 0, mkDecimal(0, mkDecimal(i, j).scale) = mkDecimal(0, abs(j) + abs(j0) - 1), i % 10 = 0 ∧ j ≠ 0
Used simplifier rules: add-c: ⊦ i + j = j + i; from specification int-basic2%add-a: ⊦ i + j + i0 = (i + j) + i0; from specification int-basic2%add-zero: ⊦ i + 0 = i; from specification int-basic2%scale-zero: ⊦ mkDecimal(0, j).scale = 0; from specification decimal%commutativity: ⊦ i * j = j * i; from specification int-mult%associativity: ⊦ i * j * j0 = (i * j) * j0; from specification int-mult%Mult-zero: ⊦ i * 0 = 0; from specification int-mult%intvalue-zero: ⊦ mkDecimal(0, j).int = 0; from specification decimal