In in this paper we establish an explicit and sharp estimate of the spectral
gap (Poincar\'{e} inequality) and the transportation inequality for Gibbs
measures, under the Dobrushin uniqueness condition. Moreover, we give a
generalization of the Liggett's M−ϵ theorem for interacting particle
systems.Comment: Published at http://dx.doi.org/10.1214/009117906000000368 in the
Annals of Probability (http://www.imstat.org/aop/) by the Institute of
Mathematical Statistics (http://www.imstat.org