A useful approximate isospin equality for charmless strange B Decays
  A useful inequality is obtained if charmless strange B decays are assumed to be dominated by the gluonic penguin diagram and the tree diagram contribution is small but not negligible. The penguin-tree interference contribution which is linear in the tree amplitude is included but the direct tree contribution which is quadratic is neglected. 
Harry J. Lipkin (Weizmann Institute of Science, Rehovot, Israel)