{s t : Lean.Omega.Constraint} →
  {x y : Lean.Omega.Coeffs} →
    (a : ℤ) →
      Lean.Elab.Tactic.Omega.Justification s x →
        (b : ℤ) →
          Lean.Elab.Tactic.Omega.Justification t y →
            Lean.Elab.Tactic.Omega.Justification (Lean.Omega.Constraint.combo a s b t) (Lean.Omega.Coeffs.combo a x b y)