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Apr 13, 2021 at 3:39 comment added Juan Sebastian Lozano @NWMT I'm not, but that definitely sounds related! I'll check it out thanks
Apr 7, 2021 at 11:11 comment added NWMT The process $x_i \to x_{i+1}$ you describe could be achieved by sampling some element $g_i$ from a symmetry group of $\Omega$ from a probability distribution $p_i$ and then $x_{i+i}=g_i\cdot x_i$.
Apr 7, 2021 at 11:01 comment added NWMT Are you aware of random walks on groups? mathoverflow.net/questions/158210/… googling also found me these notes: math.u-bordeaux.fr/~jquint/publications/CoursChili.pdf
Apr 6, 2021 at 16:24 comment added Steve Huntsman Also maybe relevant: mathoverflow.net/a/36037/1847
Apr 6, 2021 at 16:20 comment added Steve Huntsman Not sure--maybe? I don't really think of it that way. I think of it as there is a Lie group that encodes the residual freedom of any MCMC acceptance criterion. Practical acceptance criteria correspond to "tractable" elements of the Lie group. Two threads I did not really pull on are what happens if you allow negative entries and/or trying to do something a bit more elaborate along the lines at the end of section 4. Re: the latter, a decent computer algebra system will highlight some alternative if lengthy expressions that might be salient/useful.
Apr 6, 2021 at 15:39 comment added Juan Sebastian Lozano Wow that's amazing, so instead if thinking about it as an optimization problem where the lie group is encoding the distribution you think about it as a lie group encoding certain information about the invariance of the distribution, and then sampling is about moving along a vector field on that lie group?
Apr 6, 2021 at 14:22 comment added Steve Huntsman Let's think about the simpler situation $\Omega = \{1,\dots,n\} =: [n]$. For some proposal $j \in [n]$, Metropolis-Hastings corresponds to a particular simple (I hesitate to say "natural") choice of sparse matrix in the Lie algebra of the Lie group preserving the target distribution, as arxiv.org/abs/1901.08606 points out. As to the decomposition you suggest, nothing immediately comes to mind, but this is probably just a deficit of my own imagination at the moment.
Apr 6, 2021 at 5:57 history edited YCor CC BY-SA 4.0
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Apr 6, 2021 at 4:11 history asked Juan Sebastian Lozano CC BY-SA 4.0