| bitsand(bits, bits0) = [] ⊦ bits = [], bits0 = [], bits ≠ bits.first ' ∧ bits0 ≠ bits0.first ' |
⊦ bits ≠ [] ∧ bits0 = true ' → bitsand(bits, bits0) = bits
¬(bits ≠ [] ∧ bits0 = true '), bitsand(bits, bits0) = [] ⊦ bits = [], bits0 = [], bits ≠ bits.first ' ∧ bits0 ≠ bits0.first '
Used terms: bits0, bits