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Aug 30, 2018 at 15:28 comment added dohmatob Yeah the "both" was a thinko, what I really meant was "or". :)
Aug 30, 2018 at 14:20 comment added Gabe K For sure. In fact, you only need to assume that either $p$ or $q$ (not both) satisfies a log-Sobolev inequality to get this. This estimate depend on the $\rho$ in the log-Sobolev inequality, so this introduces another ingredient while eliminating the diameter.
Aug 30, 2018 at 4:20 comment added dohmatob Actually, in case of infinite diameter assuming that $p$ and $q$ both satisfy the Talagrand transportation-cost inequality, i.e $W_{d,2}(p,r)\le \sqrt{(2/\rho)\operatorname{kl}(r\|p)}$ for any distribution $r$ on $X$ relatively continuous w.r.t $p$, with a similar story for $q$ (e.g for standard Gaussian, this holds with $\rho=1$), allows us to still get an upper bound, namely $w_{d,2}(p,q) \le \sqrt{2\min (\beta\log(\beta),(1/\alpha)\log(1/\alpha))/\rho}$.
Aug 29, 2018 at 17:19 comment added dohmatob Also this document provides numerous useful inequalities between metrics on probability measures math.hmc.edu/~su/papers.dir/metrics.pdf. In general to upper bound $W$ metric with another metric, you need an upper bound on the diameter of the metric space.
Aug 29, 2018 at 17:16 comment added dohmatob OK, i can workout $TV(p,q) \le \max(1-\alpha,\beta-1)$ and so $W_d(p,q) \le \max(1-\alpha,\beta-1)\operatorname{diam}(X)$
Aug 29, 2018 at 15:03 comment added dohmatob sure. Thanks for the response (upvoted). Sure, I suspected it involve the diameter of $X$ w.r.t to $p$. See my comment section above. More precisely, it would involve something like $\sup_{x_0} \mathbb E_{x \in p} d(x,x_0)$ (which is $\le D$).
Aug 29, 2018 at 14:48 history answered Gabe K CC BY-SA 4.0