Some functorial factorizations for Quillen functors

Abstract

We prove that any right Quillen functor between arbitrary model categories admits non trivial functorial factorizations that are similar to those of a model structure. We also prove that these factorizations can be made for lax monoidal right Quillen functors. Given a monad, operad or a PROP(erad) $\mathcal{O}$, if we apply one of the factorizations to the forgetful functor $\mathcal{U} : \mathcal{O}-Alg(\mathcal{M}) \rightarrow \mathcal{M}$, we extend the theory of Quillen-Segal $\mathcal{O}$-algebras without the hypothesis of $\mathcal{M}$ being a combinatorial model category.