| i ≤ 32767, ~32768 ≤ i ⊦ 16 = # fillsgn(16, int2bits(i)), i = bits2int(lastn(16, fillsgn(16, int2bits(i)))) |
⊦ # bits ≤ n → # fillsgn(n, bits) = n
¬ # int2bits(i) ≤ 16, i ≤ 32767, ~32768 ≤ i ⊦ 16 = # fillsgn(16, int2bits(i)), i = bits2int(lastn(16, fillsgn(16, int2bits(i))))
Used terms: int2bits(i), 16