# lax = # gndx, # lax2 + # gndx < # lax0, lax0 ⊑ lax2 + lax ⊦ lax0 = []
Used simplifier rules: ⊦ # lax = 0 ↔ lax = []; (s)%f: ⊦ m < n → n ≠ 0; (forward) from specification nat-basic