| perm(a ' + x, ins≤(a, x)) ⊦ perm(ins≤(a, x), ins≤(a, y)) ↔ perm(x, y) |
perm(a ' + x, ins≤(a, x)), perm(ins≤(a, x), a ' + x) ⊦ perm(ins≤(a, x), ins≤(a, y)) ↔ perm(x, y)
Used simplifier rules: a: ⊦ (x + y) + z = x + y + z; from specification list% ⊦ perm(x, x); (s)% ⊦ perm(x + y, x + z) ↔ perm(y, z); (s)%trans: ⊦ perm(x, y) ∧ perm(y, z) → perm(x, z); (forward) from specification list-perm%sym-01: ⊦ perm(x, y) → perm(y, x); (forward) from specification list-perm