The Right Orthogonal Class $\text{GP}(R{)}^{\perp }$ via $\text{Ext}$

In this paper, we study the pair $(\text{GP}(R),\text{GP}(R{)}^{\perp })$ where $\text{GP}(R)$ is the class of all Gorenstein projective modules. We prove that it is complete hereditary cotorsion theory provided $l\mathrm{.}\text{Ggldim}(R)<\mathrm{\infty }$. We discuss also, when every Gorenstein projective module is Gorenstein flat.