| 0 ≤ 8 ∧ 0 ≤ 8 * (1 + n→i(# bytes1)) - 1, 0 < b2i(by), 2 ^ 8 * 2 ^ (8 * (1 + n→i(# bytes1)) - 1) ≤ band(255, b2i(by0)) + 256 * bytes2int(by ' + bytes1), bytes2int(by ' + bytes1) < 2 ^ ((n→i(# bytes1) + 1) * 8 - 1), ∀ by, bytes0. # bytes0 < #(bytes1 + by0 ') → true → 0 < b2i(by) → bytes2int(by ' + bytes0) < 2 ^ ((n→i(# bytes0) + 1) * 8 - 1) ⊦ |
bytes2int(by ' + bytes1) < 2 ^ ((n→i(# bytes1) + 1) * 8 - 1), 0 < b2i(by), 2 ^ (8 * (1 + n→i(# bytes1)) - 1) * 256 ≤ band(255, b2i(by0)) + 256 * bytes2int(by ' + bytes1), ∀ by, bytes0. # bytes0 < #(bytes1 + by0 ') → true → 0 < b2i(by) → bytes2int(by ' + bytes0) < 2 ^ ((n→i(# bytes0) + 1) * 8 - 1) ⊦
Used simplifier rules: ⊦ i * j = j * i;% ⊦ i * j * j0 = (i * j) * j0;% ⊦ i + j = j + i;% ⊦ i + j + i0 = (i + j) + i0;% ⊦ 0 ≤ n→i(n);% ⊦ ~1 < i ↔ 0 ≤ i;% ⊦ (* j) < i0 + (* j0) ↔ j - j0 < i0;% ⊦ 0 < i → (0 < i * j ↔ 0 < j);% ⊦ 1 ≤ i ↔ 0 < i;% ⊦ i ≤ j - i0 ↔ i + i0 ≤ j;