| # bits0 = 1, 1 ≤ # bits, ∀ bits, bits1. # bits1 < 1 → # bits1 ≤ # bits → bits = [] ∨ bits1 = [] ∨ bitsxor(bits, bits1) = bits ∨ true ∈ bits1 ⊦ bits = [], bits0 = [], bitsxor(bits, bits0) = bits, true ∈ bits0 |
⊦ # bits = 1 ↔ bits = bits.first + []
bits0 = bits0.first + [], 1 ≤ # bits, ∀ bits, bits1. # bits1 < 1 → # bits1 ≤ # bits → bits = [] ∨ bits1 = [] ∨ bitsxor(bits, bits1) = bits ∨ true ∈ bits1 ⊦ bits = [], bits0 = [], bitsxor(bits, bits0) = bits, true ∈ bits0
Used terms: bits0