| ¬(1 < # bits ∧ 1 < # bits0), # bits0 ≤ # bits, ∀ bits, bits1. # bits1 < # bits0 → # bits1 ≤ # bits → bits1 = [] ∨ bitsand(bits, bits1) = bits1 ∨ false ∈ bits ∨ bits1.first ⊦ bitsand(bits, bits0) = bits0, bits0 = [], bits0.first, false ∈ bits |
# bits0 ≤ # bits, ∀ bits, bits1. # bits1 < # bits0 → # bits1 ≤ # bits → bits1 = [] ∨ bitsand(bits, bits1) = bits1 ∨ false ∈ bits ∨ bits1.first ⊦ bitsand(bits, bits0) = bits0, bits0 = [], bits = [], bits0.first, false ∈ bits, # bits0 ≠ 1 ∧ # bits ≠ 1
Used simplifier rules: ⊦ m ≤ 0 ↔ m = 0;% ⊦ # [] = 0;% ⊦ # bits = 0 ↔ bits = [];% ⊦ 1 < m ↔ ¬(m = 0 ∨ m = 1);