  Macroscopic polarization, both of intrinsic and piezoelectric nature, is
unusually strong in III-V nitrides, and the built in electric fields in the
layers of nitride-based nanostructures, stemming from polarization changes at
heterointerfaces, have a major impact on the properties of single and multiple
quantum wells, high mobility transistors, and thin films. The concepts involved
in the theory and applications of polarization in nitrides have encountered
some resistance in the field. Here we discuss critically ten ``propositions''
aimed at clarifying the main controversial issues.
