⊦ ri = rj ↔ ri.num = rj.num ∧ ri.denom = rj.denom
rational(i, j).num = rational(i0, j).num ∧ rational(i, j).denom = rational(i0, j).denom, 0 < j ⊦ i = i0
Used terms: rational(i0, j), rational(i, j)