Ciro Santilli @cirosantilli 37

Unit of electric current.

Affected by the ampere in the 2019 redefinition of the SI base units.

Some courses at least allow you to see material for free, e.g.: www.coursera.org/learn/quantum-optics-single-photon/lecture/UYjLu/1-1-canonical-quantization. Lots of video focus as usual for MOOCs.

Some are paywalled: www.coursera.org/learn/theory-of-angular-momentum?specialization=quantum-mechanics-for-engineers

It is extremely hard to find the course materials without enrolling, even if enrolling for free! By trying to make money, they make their website shit.

The comment section does have a lot of activity: www.coursera.org/learn/statistical-mechanics/discussions/weeks/2! Nice. And works like a proper issue tracker. But it is also very hidden.

November 2023 topics:

Basically it is a larger space such that there exists a surjection from the large space onto the smaller space, while still being compatible with the topology of the small space.

We can characterize the cover by how injective the function is. E.g. if two elements of the large space map to each element of the small space, then we have a double cover and so on.

It gets the job done, but cannot make a large codebase DRY without insanity.

As of 2020, C is like Latin, and we are in the Middle Ages, where it has become a lingua franca.

It is interesting to note how late C appeared: 1972, compared e.g. to Fortran which is from 1957. This is basically because C was a "systems programming language", i.e. with focus on pointer manipulation, and because early computers were so weak, there was no operating system or many software layers in the early days. Fortran however was a numerical language, and it ran directly on bare metal, an application that existed before systems programming.

Examples under c.

promoter for the E. Coli K-12 MG1655 operon thrLABC.

Yup, this one Focks you up.

Richard Feynman's mentor at Princeton University, and notable contributor to his development of quantum electrodynamics.

Worked with Niels Bohr at one point.

Web of Stories interview (1996): www.youtube.com/playlist?list=PLVV0r6CmEsFzVlqiUh95Q881umWUPjQbB. He's a bit slow, you wonder if he's going to continute or not! One wonders if it is because of age, or he's always been like that.

This is the one Ciro Santilli envies the most, because he has such a great overlap with Ciro's interests, e.g.:

www.reddit.com/r/JordanPeterson/comments/gc23gd/petersons_online_university_still_a_thing/.

~1TB.

Has a separate power cord, not USB powered. Unbelievable. Edit: actually high ends are still like that as of 2023, e.g. at that time, a the max non-cabled was 5 TB, but top of line was 20 TB.

Disk label: wd1t.

Ubuntu 20.04 gnome-disks benchmark, ext4 partition: 37MB/s.

Take the element and apply it to itself. Then again. And so on.

In the case of a finite group, you have to eventually reach the identity element again sooner or later, giving you the order of an element of a group.

The continuous analogue for the cycle of a group are the one parameter subgroups. In the continuous case, you sometimes reach identity again and to around infinitely many times (which always happens in the finite case), but sometimes you don't.

Bibliography: discuss.bbchallenge.org/t/decider-cyclers/33

Example: bbchallenge.org/279081.

These are very simple, they just check for exact state repetitions, which obviously imply that they will run forever.

Unfortunately, cyclers may need to run through an initial setup phase before reaching the initial cycle point, which is not very elegant.

Also, we have no way of knowing the initial setup length of the actual cycle length, so we just need an arbitrary cutoff value.

And unfortunately, this can lead to misses, e.g. Skelet machine #1, a 5 state machine, has a (translated) cycle that starts at around 50-200M steps, and takes 8 trillion steps to repeat.

Given a matrix $A$ with metric signature containing $m$ positive and $n$ negative entries, the indefinite orthogonal group is the set of all matrices that preserve the associated bilinear form, i.e.:Note that if $A=I$, we just have the standard dot product, and that subcase corresponds to the following definition of the orthogonal group: Section "The orthogonal group is the group of all matrices that preserve the dot product".

As shown at all indefinite orthogonal groups of matrices of equal metric signature are isomorphic, due to the Sylvester's law of inertia, only the metric signature of $A$ matters. E.g., if we take two different matrices with the same metric signature such as:and:both produce isomorphic spaces. So it is customary to just always pick the matrix with only +1 and -1 as entries.

Ciro Santilli likes this.

He doesn't have the patience to actually watch full episodes with rare exceptions, rather just watching selected scenes from: www.youtube.com/channel/UCdeIGY2DIjpGf0A2m9GSE3g, but still, it is interesting.

What appeals to Ciro in this series is how almost nothing is solved by violence, almost everything is decided in the bridge, at the "cerebral" level of the command structure. This reminds Ciro of a courtroom of law sometimes.

Maybe there's also a bit of 90's nostalgia involved too though, as this is something that would show on some random cable channels a bored young Ciro would have browsed during weekends, never really watching full episodes.

One crime of many episodes is being completely based on some stupid new scientific concept, which any character to back it up.

Another thing that hurt is that due to their obsession with the senior members of the crew, sometimes those senior members are sent in ridiculously risky operations, which is very unrealistic.

Episodes that Ciro watched fully and didn't regret:

Semi worth it:

Not worth it:

Stefan Hell was really excited by this as of 2023.

Instead of shining a light over the entire sample to saturate it, you illuminate just a small bit instead.

He was basically saying that this truly brings the resolution to the actual physical limits, going much much beyond 2014 Nobel prize levels.

This is what happens when you apply a step voltage to a series RC circuit: TODO $I(t)$ graph.