On a Gibbs characterization of normalized generalized Gamma processes

Circumventing the need for an analytical approach, we provide an alternative derivation of a Gibbs characterization of normalized generalized Gamma processes recently obtained in Lijoi et al. [Lijoi, A., Prünster, I., Walker, S.G., 2008. Investigating nonparametric priors with Gibbs structure. Statist. Sin. (in press)], by exploiting a Pitman's characterization of exponentially tilted Poisson-Kingman models.