Sam Power

@spmontecarlo.bsky.social

Lecturer in Maths & Stats at Bristol. Interested in probabilistic + numerical computation, statistical modelling + inference. (he / him). Homepage: https://sites.google.com/view/sp-monte-carlo Seminar: https://sites.google.com/view/monte-carlo-semina

Always interesting to see the different responses to the various items of maths news as they come out. I feel like I find it important to keep reminding myself that even for fairly proximate fields to mine within maths, there are lots of internal cultural aspects on which I'm not well-informed.

Just to give some context: let F be a function that is reasonably continuous but not quite Lipschitz (e.g. Hölder cts). Then, define F_t (x) = sup { F(y) - t || x - y|| }. Then F_t is t-Lipschitz, and pointwise, F(x) < F_t (x) < F(x) + c_t for some constant offset c_t.

Sam Power@spmontecarlo.bsky.social · 7d ago

I feel like this phenomenon is somehow quietly omnipresent around convex optimisation; a little bit of differentiability is never too far away, but asking for too much differentiability is a bit dangerous.

Lots of interesting bits and pieces cropping up in (what I've encountered of) Tao's ICM talk. I do find that this aspect of 'digestion' of mathematics is generally quite exciting to me, particularly in terms of revisiting established work. (I do understand why it's less lucrative in the short term)

Bild

A pair of notes which review and optimise a couple of fun (and by now, reasonably well-established) techniques for showing the 'contraction-on-average' property for stochastic systems, focusing on problems for which the 'obvious' metrics do not contract. (links below)

BildBild

(presumably) late to the game, but have been reading a little bit about { Proof Theory / Proof Mining / Skolemization } this afternoon, which has been sort of interesting, especially as someone with a bit of a taste for quantitative results and so on.

I have just resigned from the board of "Statistics and Computing", along with 17 other Associate Editors. This was a difficult decision: this great journal has published many tremendous articles under the leadership of EiC Ajay Jasra, and before him David Hand, Gilles Celeux, and Mark Girolami.

New version available at the same address! We bit the bullet and extended the work to consider arbitrary numbers of blocks, discrete spaces, parallel/systematic/random scan CAVI within a unified framework. Applications now include statistical physics models and others! arxiv.org/abs/2605.30253

Sam Power@spmontecarlo.bsky.social · 2mo ago

With friends at the University of Warwick (in particular, Rocco Caprio and @adriencorenflos.bsky.social), we've recently arXived some work (arxiv.org/abs/2605.30253) on a method for approximate inference known as "Coordinate Ascent Variational Inference", or "CAVI" for short. Let me explain:

Having a nice period at the moment wherein working through the details of basic examples (or examples for basic techniques) points neatly in the direction of new results, either in the sense of suggesting proofs in the general case, or at least in the sense of "it's worth following up on this".

Meaningless grumble: I wish that the "forward process" / "reverse process" terminology for diffusion models had instead been "noising process" and "denoising process". Feels a bit related to how I find ambiguity in the use of "top-down" and "bottom-up" w.r.t. neural networks.

Something which I've realised is very true about my approach to mathematics research is that I'll occasionally see a proof technique ( / assumption / theoretical framework / ... ) so good that I will go out of my way to find a reason to use it for myself. Not sure how prevalent it is (maybe quite?).