On Classification of Models of Large Local-Type Non-Gaussianity
  We classify models generating large local-type non-Gaussianity into some
categories by using some "consistency relations" among the non-linearity
parameters f_{NL}^{local}, \tau_{NL}^{local} and g_{NL}^{local}, which
characterize the size of bispectrum for the former and trispectrum for the
later two. Then we discuss how one can discriminate models of large local-type
non-Gaussianity with such relations. We first classify the models by using the
ratio of \tau_{NL}^{local}/(6f_{NL}^{local}/5)^2, which is unity for
"single-source" models and deviates from unity for "multi-source" ones. We can
make a further classification of models in each category by utilizing the
relation between f_{NL}^{local} and g_{NL}^{local}. Our classification suggests
that observations of trispectrum would be very helpful to distinguish models of
large non-Gaussianity and may reveal the generation mechanism of primordial
fluctuations.
