This document is the aggregation of six discussions of Lopes et al. (2010)
that we submitted to the proceedings of the Ninth Valencia Meeting, held in
Benidorm, Spain, on June 3-8, 2010, in conjunction with Hedibert Lopes' talk at
this meeting, and of a further discussion of the rejoinder by Lopes et al.
(2010). The main point in those discussions is the potential for degeneracy in
the particle learning methodology, related with the exponential forgetting of
the past simulations. We illustrate in particular the resulting difficulties in
the case of mixtures.Comment: 14 pages, 9 figures, discussions on the invited paper of Lopes,
Carvalho, Johannes, and Polson, for the Ninth Valencia International Meeting
on Bayesian Statistics, held in Benidorm, Spain, on June 3-8, 2010. To appear
in Bayesian Statistics 9, Oxford University Press (except for the final
discussion
