∀ (C : Type u) [inst : CategoryTheory.Category.{v, u} C] [inst_1 : HomotopicalAlgebra.CategoryWithWeakEquivalences C]
  [inst_2 : HomotopicalAlgebra.CategoryWithCofibrations C] [(HomotopicalAlgebra.cofibrations C).IsStableUnderRetracts]
  [(HomotopicalAlgebra.weakEquivalences C).IsStableUnderRetracts],
  (HomotopicalAlgebra.trivialCofibrations C).IsStableUnderRetracts