| i0 < 0, 256 * i0 + j < 0, j < 0, ~256 < j, 256 * i0 + j < ~128, j < ~128 ⊦ 8 = # fillsgn(8, int2bits(j).rest), b2i(i2b(bits2int(lastn(8, int2bits(i0 - 1) + fillsgn(8, int2bits(j).rest))))) = 256 + j |
⊦ # bits ≤ n → # fillsgn(n, bits) = n
¬ # int2bits(j).rest ≤ 8, i0 < 0, 256 * i0 + j < 0, j < 0, ~256 < j, 256 * i0 + j < ~128, j < ~128 ⊦ 8 = # fillsgn(8, int2bits(j).rest), b2i(i2b(bits2int(lastn(8, int2bits(i0 - 1) + fillsgn(8, int2bits(j).rest))))) = 256 + j
Used terms: int2bits(j).rest, 8