⊦ ∃ i, j. ri = rational(i, j) ∧ 0 < j
∃ i, j. rj = rational(i, j) ∧ 0 < j, 0 < j ⊦ (rational(i, j) + rj) + rj0 = rational(i, j) + rj + rj0
Used terms: rj