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