Remarks on the Rellich inequality
  We study the Rellich inequalities in the framework of equalities. We present equalities which imply the Rellich inequalities by dropping remainders. This provides a simple and direct understanding of the Rellich inequalities as well as the nonexistence of nontrivial extremisers. 
Shuji Machihara, Tohru Ozawa, Hidemitsu Wadade
math.CA