George M. Bergman, Coproducts and Some Universal Ring Constructions, Transactions of the American Mathematical Society, Vol. 200 (Dec., 1974), pp. 33-88 ...

Theorem. Let R and T be somewhat commutative algebras with the same halmonic number and let ϕ : R → T be an algebra homomorphism. Then every holnomic T-module M is via ϕ a holonomic R-module and has ...