Ciro Santilli @cirosantilli 34

After removing it:

Of course, we already knew that minimal plaster work would be needed from the start, since we have to hammer two small nails into the wall. But that level of damage might have been easily dealt with by a non-professional tenant himself. But the level I had was a bit more than I felt I should handle myself.

To Ciro Santilli, a key observation is:Clearly the rich will be much, much more shielded by keeping large parts of their wealth in shares... from this point of view, it is insane to print money!!! Tax the rich instead...

Mentions:

A linear map is a function $f:V_1(F)\to V_2(F)$ where $V_1(F)$ and $V_2(F)$ are two vector spaces over underlying fields $F$ such that:

A common case is $F=\mathbb{R}$, $V_1={\mathbb{R}}_m$ and $V_2={\mathbb{R}}_n$.

One thing that makes such functions particularly simple is that they can be fully specified by specifyin how they act on all possible combinations of input basis vectors: they are therefore specified by only a finite number of elements of $F$.

Every linear map in finite dimension can be represented by a matrix, the points of the domain being represented as vectors.

As such, when we say "linear map", we can think of a generalization of matrix multiplication that makes sense in infinite dimensional spaces like Hilbert spaces, since calling such infinite dimensional maps "matrices" is stretching it a bit, since we would need to specify infinitely many rows and columns.

The prototypical building block of infinite dimensional linear map is the derivative. In that case, the vectors being operated upon are functions, which cannot therefore be specified by a finite number of parameters, e.g.

For example, the left side of the time-independent Schrödinger equation is a linear map. And the time-independent Schrödinger equation can be seen as a eigenvalue problem.

Ciro Santilli's LinkedIn profile: www.linkedin.com/in/cirosantilli/ see also: accounts controlled by Ciro Santillis.

LinkedIn fully complies with censorship imposed locally by the Chinese government, and does so in a non-transparent way: cirosantilli.com/china-dictatorship/linkedin.

It is hard to understand what the point of that website is, as it is basically just a more closed version of Facebook, but alas, it has flourished as the only place where people post more useful content compared to Twitter and Facebook. In any case, Ciro just applies the same unfollow policy to all of them: aggressively filter your social media follows.

Impossible to hide your current location?

Ciro Santilli used to read books when he was younger (Harry Potter up to the 4th, Lord of the Rings), but once you are reading code, technical articles and news the whole day, you really just want to watch videos of people doing useless things on YouTube to rest, enough text.

Books are slow. No patience. Need faster immediate satisfaction.

Paradoxically Ciro feels like he's becoming a writer of sorts though, one semi independent section/answer/piece of knowledge at a time.

Writing is not just giving out information. It is re-feeling it.

NIST database for spectral line: physics.nist.gov/PhysRefData/ASD/lines_form.html

Let's do a sanity check.

Searching for "H" for hydrogen leads to: physics.nist.gov/cgi-bin/ASD/lines1.pl?spectra=H&limits_type=0&low_w=&upp_w=&unit=1&submit=Retrieve+Data&de=0&format=0&line_out=0&en_unit=0&output=0&bibrefs=1&page_size=15&show_obs_wl=1&show_calc_wl=1&unc_out=1&order_out=0&max_low_enrg=&show_av=2&max_upp_enrg=&tsb_value=0&min_str=&A_out=0&intens_out=on&max_str=&allowed_out=1&forbid_out=1&min_accur=&min_intens=&conf_out=on&term_out=on&enrg_out=on&J_out=on

From there we can see for example the 1 to 2 lines:

We see that the table is sorted from lower from level first and then by upper level second.

So it is good to see that we are in the same 121nm ballpark as mentioned at hydrogen spectral line.

TODO why I can't see 2s to 2p transitions there to get the fine structure?

While learning black-hole stuff is not on top of Ciro Santilli's priorities, Hawking's spirit is to be admired.

To never give up even when everything seems lost, and still have a sense of humour is respectable.

An ex-physicist colleague who had met Hawking told an anecdote. Hawking was around in the department one day, they said hi and all. But then Hawking wanted to tell a joke. It took like 5 minutes of typing, and you can imagine that things were pretty awkward and the joke's timing was "a bit off". But Hawking did tell the joke nonetheless.

This is also suggested in the The Theory of Everything (2014) film, and therefore likely the biographies.

Brand according to documents: SMEG.

Most similar models I an find: www.smeguk.com/products/UKC8173N1F and www.smeguk.com/products/UKC81721F, the keyword are "built-in" and "integrated", other very similar ones: www.smeguk.com/refrigerators/built-in

Looks like this: www.youtube.com/watch?v=4c_LBVnU4ec and that's how to unclog the drain.

2020-11-28: defrost. Some small Styrofoam was broken lose from top, noticed small burn or rust marks on top grid nearby.

There are actually two possible definitions for the DFT:

The $1/\sqrt{N}$ is nicer mathematically as the inverse becomse more symmetric, and power is conserved between time and frequency domains.

TODO. I think this is the key point. Notably, $U(1)$ symmetry implies charge conservation.

More precisely, each generator of the corresponding Lie algebra leads to one separate conserved current, such that a single symmetry can lead to multiple conserved currents.

This is basically the local symmetry version of Noether's theorem.

Then to maintain charge conservation, we have to maintain local symmetry, which in turn means we have to add a gauge field as shown at Video "Deriving the qED Lagrangian by Dietterich Labs (2018)".

Forces can then be seen as kind of a side effect of this.

Bibliography:

This section is about telecommunication systems that are based on top of telephone lines.

Telephone lines were ubiquitous from early on, and many technologies used them to send data, including much after regular phone calls became obsolete with VoIP.

These market forces tended to eventually crush non-telephone-based systems such as telex. Maybe in that case it was just that the name sounded like a thing of the 50's. But still. Dead.

Who needs a hackable general purpose computer, when you can buy a completely locked down computer that only runs useless programs for which you have to pay thousands of dollars to develop for, cannot run a large percentage of major titles from competitor hardware due to business deals (see also) and will inevitably reach planned obsolescence in 4 years?

By company:

Local symmetries appear to be a synonym to internal symmetry, see description at: Section "Internal and spacetime symmetries".

As mentioned at Quote , local symmetries map to forces in the Standard Model.

Appears to be a synonym for: gauge symmetry.

A local symmetry is a transformation that you apply a different transformation for each point, instead of a single transformation for every point.

TODO what's the point of a local symmetry?

Bibliography:

Amazing talk by Richard Feynman that describes his experiences at Los Alamos National Laboratory while developing the first nuclear weapons.

Transcript: calteches.library.caltech.edu/34/3/FeynmanLosAlamos.htm Also included full text into Surely You're Joking, Mr. Feynman.

These appear to be benchmarks that don't involve running anything concretely, just compiling and likely then counting gates:

Paging is implemented by the CPU hardware itself.

Paging could be implemented in software, but that would be too slow, because every single RAM memory access uses it!

Operating systems must setup and control paging by communicating to the CPU hardware. This is done mostly via:

Processes can however make requests to the OS that cause the page tables to be modified, notably:

The kernel then decides if the request will be granted or not in a controlled manner.

Similar to: www.amazon.co.uk/dp/B013AV45IS

2019: broke with sign number 6. Ciro Santilli opened it up a bit destructively.

How to open: www.youtube.com/watch?v=8Lf68mAB0Vk