⌜a '⌝ + ⌜x⌝ = ⌜a0 '⌝ + σ0 ⊦ a = a0 ∧ ⌜x⌝ = σ0
⌜a '⌝ + ⌜nf⌝ = ⌜a0 '⌝ + σ0 ⊦ a = a0 ∧ ⌜nf⌝ = σ0
Used simplifier rules: stream freely generated by ⌜ ⌝, ⌜ ⌝;;