Ciro Santilli @cirosantilli 40

Of course those racist Nazis are a bunch of idiots, but how can you be surprised when freedom-of-speech focused tech gets used by them? www.theverge.com/2019/7/12/20691957/mastodon-decentralized-social-network-gab-migration-fediverse-app-blocking

Obviously, a few large instances dominate the user base for all practical purposes: kevq.uk/centralisation-and-mastodon/. And likely the network splits into hate-speech/non-hate-speech blacklist boundaries. And since the dominating closed networks will never lose user counts (???), the only instance that dominates will be the main hate speech one.

The flagship instance was mastodon.social and then in 2020 they closed signups for it and created a secondary mastodon.online.

The multi-instance thing is confusing and problematic. E.g. replies and likes might not show up across instances in some occasions: www.reddit.com/r/Mastodon/comments/ynt7ta/is_there_a_way_to_see_post_replies_displayed_on/

The "advanced interface" feature is bad. Really bad. MacOS file browser inspired.

You label cells with isotopes rather than fluorescent substances. Vendors claim that this allows much wider N-way sorts, e.g. 2022 Fluidigm claims around 40/50, because the fluorecent spectrum is too wide to do much more than 7/8 way splits.

Best busy beaver machine known since 1989 as of 2023, before a full proof of all 5 state machines had been carried out.

Entry on The Busy Beaver Challenge: bbchallenge.org/1RB1LC_1RC1RB_1RD0LE_1LA1LD_1RZ0LA

Paper extracted to HTML by Heiner Marxen: turbotm.de/~heiner/BB/mabu90.html

They split up from the rest of the mammals after the monotremes.

Every other mammal has a placenta.

This baby in pouch thing just feels like a pre-placenta stage.

Like all big names in science, she was at the right place at the right time and with the right interest and passion.

Notably, the man she married, Pierre Curie, happened to be a the world master at precisely the technique that she needed to carefully measure radioactivity: he had the most precise electrometers in the world, which allowed to detect small amounts of radioactivity via the ionization of air by radiation . These used piezoelectricity, which Pierre Curie co-discovered with his brother.

Possibly fake, but memorable:

Gospel of Matthew 4:4:

Ciro Santilli's mother loves that one. Even though she was constantly worried that if Ciro had studied physics he would be poor and starve, a factor which led him to study engineering instead, one of the greatest mistakes of his life. don't be a pussy.

It is so close that we can notice its proper motion, and its distance to us will vary significantly across a few tens of thousands of years!

We map each point and a small enough neighbourhood of it to ${\mathbb{R}}^n$, so we can talk about the manifold points in terms of coordinates.

Does not require any further structure besides a consistent topological map. Notably, does not require metric nor an addition operation to make a vector space.

Manifolds are cool. Especially differentiable manifolds which we can do calculus on.

A notable example of a Non-Euclidean geometry manifold is the space of generalized coordinates of a Lagrangian. For example, in a problem such as the double pendulum, some of those generalized coordinates could be angles, which wrap around and thus are not euclidean.

Each elliptic space can be modelled with a real projective space. The best thing is to just start thinking about the real projective plane.

A unique projective space can be defined for any vector space.

The projective space associated with a given vector space $V$ is denoted $\mathbf{P}(V)$.

The definition is to take the vector space, remove the zero element, and identify all elements that lie on the same line, i.e. $\vec{v}=\lambda \vec{w}$

The most important initial example to study is the real projective plane.