Extension of local-type inequality for the higher order correlation
  functions
  For the local-type primordial perturbation, it is known that there is an
inequality between the bispectrum and the trispectrum. By using the
diagrammatic method, we develop a general formalism to systematically construct
the similar inequalities up to any order correlation function. As an
application, we explicitly derive all the inequalities up to six and
eight-point functions.
