| ∀ bits1, bits0. # bits1 < # bits → true → bits1 = [] ∨ bits0 = [] ∨ bitsor(bits1, bits0) = bitsinvert(bitsand(bitsinvert(bits1), bitsinvert(bits0))) ⊦ bits0 ≠ bits0.first ', bitsor(bits, bits0) = bitsinvert(bitsand(bitsinvert(bits), bitsinvert(bits0))), bits0 = [], bits = [], bits0 = true ', bits0 = false ', bits = true ', bits = false ' |
bits0 = bits0.first ', ∀ bits1, bits0. # bits1 < # bits → true → bits1 = [] ∨ bits0 = [] ∨ bitsor(bits1, bits0) = bitsinvert(bitsand(bitsinvert(bits1), bitsinvert(bits0))) ⊦ bits = false ', bits = true ', bits0 = false ', bits0 = true ', bits = [], bits0 = [], bitsor(bits, bits0) = bitsinvert(bitsand(bitsinvert(bits), bitsinvert(bits0)))