**4.4.2. Gaussianity and adiabaticity**

While gaussianity and adiabaticity are predictions of the simplest models, it is well advertised that there exist inflationary models which violate these hypotheses. Whether observations violating gaussianity or adiabaticity would exclude inflation depends on the type observed. For example, chi-squared distributed perturbations are relatively easy to generate from inflation, by ensuring that the leading contribution to perturbations is the square of a gaussian field. On the other hand, it would be pointless to try and find an inflation model if line discontinuities in the microwave sky were discovered.