| perm(x, x0), perm(x + y, y0 + x0) ⊦ perm(y, y0) |
perm(x, x0), perm(x + y, y0 + x0), perm(x0, x), perm(y0 + x0, x + y) ⊦ perm(y, y0)
Used simplifier rules: sym-01: ⊦ perm(x, y) → perm(y, x);%sym-02: ⊦ ¬ perm(x, y) → ¬ perm(y, x);%sym-02: ⊦ ¬ perm(x, y) → ¬ perm(y, x);%trans: ⊦ perm(x, y) ∧ perm(y, z) → perm(x, z);%ref: ⊦ perm(x, x);%app: ⊦ perm(x + y, x + z) ↔ perm(y, z);%a: ⊦ (x + y) + z = x + y + z; from specification list