⊦ even(i + j) ↔ even(i) ∧ even(j) ∨ odd(i) ∧ odd(j)
even(i1), odd(i2), even(i0), odd(i) ⊦ (even(i1) ∧ even(i0) ∨ odd(i1) ∧ odd(i0)) ∧ even(i2 + i)
Used terms: i0, i1