a cotorsion theory in the homotopy category of complexes of flat $r$-modules

This note is devoted to the study of cotorsion theory in the homotopy category of flat r-modules, k(flat-r). let r be an arbitrary ring and k(dg-cotf-r) be the homotopy category of all dg-cotorsion complexes of flat r-modules. it is proved that (kp(flat-r), k(dg-cotf-r))forms a complete cotorsion pair in k(flat-r), where kp(flat-r) is the subcategory of all flat complexes.