Evans-Lewis inequalities in dimension three

In proving Rellich inequalities in the framework of equalities, N. Bez, S. Machihara, and T. Ozawa obtained some interesting norm inequalities in the spirit of Evans and Lewis that compare the standard Laplacian with its radial and spherical components. In this paper we give a simple unified proof and a strict improvement of these Evans-Lewis inequalities in the subtle dimension three case. Our approach is robust and explains clearly the occurrence of the sharp constant.
Comment: added a section which extends our machinery to the abstract framework; added more references