| # y = n0, # y + # z = n0 + n, n ≤ # y + # z ⊦ ∃ y0, z0. y + z = y0 + z0 ∧ # z0 = n |
⊦ ∃ y0, z0. y + z = y0 + z0 ∧ # z0 = # z
Used simplifier rules: ⊦ m ≤ m + n; (s)%c: ⊦ m + n = n + m; from specification nat-basic%a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic% ⊦ m + n = m + n0 ↔ n = n0; (s)