| # x1 = # x, ⌜x1⌝ + ⌜nf0⌝ = ⌜x⌝ + ⌜nf⌝ , a = a0, ∀ x0, nf0, nf. # x = # x0 ∧ ⌜x1⌝ + ⌜nf0⌝ = ⌜x0⌝ + ⌜nf⌝ → x1 = x0 ∧ nf0 = nf ⊦ a = a0 ∧ x1 = x ∧ nf0 = nf |
# x1 = # x, ⌜x1⌝ + ⌜nf0⌝ = ⌜x⌝ + ⌜nf⌝ , ∀ x0, nf0, nf. # x = # x0 ∧ ⌜x1⌝ + ⌜nf0⌝ = ⌜x0⌝ + ⌜nf⌝ → x1 = x0 ∧ nf0 = nf ⊦ x1 = x ∧ nf0 = nf