| ⊦ bits = [], bits0 = [], lastn(n, fillsgn(n, bitsand(lastn(n, fillsgn(n, bits)), bits0))) = lastn(n, fillsgn(n, bitsand(bits, bits0))) |
⊦ n ≤ # bits → fillsgn(n, bits) = bits
¬ n ≤ # bits ⊦ bits = [], bits0 = [], lastn(n, fillsgn(n, bitsand(lastn(n, fillsgn(n, bits)), bits0))) = lastn(n, fillsgn(n, bitsand(bits, bits0)))
n ≤ # bits ⊦ bits = [], bits0 = [], lastn(n, fillsgn(n, bitsand(lastn(n, bits), bits0))) = lastn(n, fillsgn(n, bitsand(bits, bits0)))
Used terms: bits, n