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There have been several recent advances in number theory, culminating with leanprover-community/mathlib#9071. Anne will tell us about it.

See for example https://leanprover-community.github.io/blog/posts/month-in-mathlib-aug-2022/.

See https://leanprover.zulipchat.com/#narrow/stream/217875-Is-there.20code.20for.20X.3F/topic/Reindexing.20a.20dependent.20product

Yury wants to finish writing a paper and then a blog post.

This is also discussed in some comments on #9 .

We already have an "API" for linking to and displaying declarations: there's a json file hosted with the docs page that maps declaration names to their locations in docs and source, and a pretty-printed, linkified display of the declaration's type. This is used, for instance, in the 100 theorems page.

It might make sense to use this in the blog too, in at least two scenarios:

• If you display a declaration inline, like absolutely_continuous_iff_with_density_radon_nikodym_deriv_eq, we could print it as in the 100 theorems page. Unfortunately the API won't print declaration bodies, nor is this easy to do, so things like def measure.singular_part above would be harder.
• If you refer to a declaration by name without displaying it, like "In Lean, this is shown by absolutely_continuous_iff_with_density_radon_nikodym_deriv_eq and can be found in measure_theory/decomposition/radon_nikodym.", we could automatically link to the updated location in docs and/or source. This is not robust to name changes though.

Moreover, every blog build would check for links broken by name changes.

How to implement this though? I'm not sure how much control we get over Nikola's markdown processing. I couldn't tell after glancing at the docs what md processor it uses. We need something triggered by a particular regex pattern, more involved than a linkifier.

This also doesn't address the concern that as declarations change in mathlib over time, blog posts could become out of date.

Jeremy will tell us about https://www.cmu.edu/news/stories/archives/2021/september/hoskinson-center-for-formal-mathematics.html

On the page https://leanprover-community.github.io/blog/ clicking Main Site leads me to https://leanprover-community.github.io/blog/
On any other page this link leads me to https://leanprover-community.github.io/ as expected.

There have been a massive refactor of linear map to make room for semi-linear maps (in particular over complex vector spaces). Frédéric Dupuis should write something about this, see https://leanprover.zulipchat.com/#narrow/stream/116290-rss/topic/Recent.20Commits.20to.20mathlib.3Amaster/near/254673184. He didn't promise anything yet.

Rémy Degenne will write a post about probability in mathlib and the quest for conditional expectation.
See https://leanprover.zulipchat.com/#narrow/stream/116290-rss/topic/Recent.20Commits.20to.20mathlib.3Amaster/near/254711317 and following messages. This should happen around October 20th.

Johan promised he will soon write a small update of the Liquid Tensor Experiment progress status.