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 a $\Delta I = 0$ transition like that from the gluonic penguin diagram and the contributions of all other diagrams including the tree, electroweak penguin and annihilation diagrams are small but not negligible. The interference contributions which are linear in these other amplitudes are included but the direct contributions which are quadratic are neglected.