Vitali Vougalter, Vitaly Volpert On the solvability conditions for the diffusion equation with convection terms (182K, pdf) ABSTRACT. Linear second order elliptic equation describing heat or mass diffusion and convection on a given velocity field is considered in R^3. The corresponding operator L may not satisfy the Fredholm property. In this case, solvability conditions for the equation Lu=f are not known. In this work, we derive solvability conditions in H^2(R^3) for the non self-adjoint problem by relating it to a self-adjoint Schroedinger type operator, for which solvability conditions are obtained in our previous work.