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