Cool Pions move at less than the speed of light

At nonzero temperature, pions propagate through a thermal medium at less than the speed of light. About low temperature, this effect begins not at $\sim T^2$, but at next to leading order, $\sim T^4$. We also derive the generalization of the relation of Gell-Mann, Oakes, and Renner to nonzero temperature.Comment: 11 pages, latex + sprocl.sty, talk given at Continuous Advances in QCD'96, Minneapoli

Bayesian Core: The Complete Solution Manual

This solution manual contains the unabridged and original solutions to all the exercises proposed in Bayesian Core, along with R programs when necessary.Comment: 118+vii pages, 21 figures, 152 solution

Transversely Hessian foliations and information geometry

A family of probability distributions parametrized by an open domain $\Lambda$ in $R^n$ defines the Fisher information matrix on this domain which is positive semi-definite. In information geometry the standard assumption has been that the Fisher information matrix tensor is positive definite defining in this way a Riemannian metric on $\Lambda$. If we replace the "positive definite" assumption by the existence of a suitable torsion-free connection, a foliation with a transversely Hessian structure appears naturally. In the paper we develop the study of transversely Hessian foliations in view of applications in information geometry