| ¬ 8 ≤ # int2bits(i) ⊦ bitsand(lastn(8, fillsgn(8, int2bits(i))), int2bits(j)) = [], lastn(8, fillsgn(8, bitsand(int2bits(i), int2bits(j)))) = lastn(8, fillsgn(8, bitsand(lastn(8, fillsgn(8, int2bits(i))), int2bits(j)))) |
# int2bits(i) < 8 ⊦ lastn(8, fillsgn(8, bitsand(int2bits(i), int2bits(j)))) = lastn(8, fillsgn(8, bitsand(lastn(8, fillsgn(8, int2bits(i))), int2bits(j)))), bitsand(lastn(8, fillsgn(8, int2bits(i))), int2bits(j)) = []
Used simplifier rules: ⊦ m < n → n ≠ 0; (forward)% ⊦ ¬ m ≤ n ↔ n < m;