Ciro Santilli @cirosantilli 37

Their websites a bit shitty, clearly a non cohesive amalgamation of several different groups.

E.g. you have to create several separate accounts, and different regions have completely different accounts and websites.

The Europe replacement part website for example is clearly made by a third party called flex.com/ and has Flex written all over it, and the header of the home page has a slightly broken but very obviously broken CSS. And you can't create an account without a VAT number... and they confirmed by email that they don't sell to non-corporate entities without a VAT number. What a bullshit!

This is true. The level of competition in university entry exams in Asia in insane in the early 21st century compared to the West.

This is actually both good and bad. Good because it selects some very good exam passers. And bad because it selects some very good exam passers.

Related:

The first time Ciro Santilli Googled this was when trying to repair his cell phone.

2019 cell phones are glued together with adhesive, which makes them impossible to repair them unless you have a heat gun, spend hours and hours learning and planning, and accept the risk of breaking the screen

Repairability scores: www.ifixit.com/smartphone-repairability

If you take a phone less than 300 dollars to a repair shop in the first world, they will say: I've never repaired this crap, and likely for the price of the repair you should just buy a new one, and so to the trash goes the old one, polluting the planet, and in comes a new one, enriching the manufacturer further.

European Union, I need you now.

Oh, there is some 2017 EU action actually: (archive) www.europarl.europa.eu/news/en/press-room/20170629IPR78633/making-consumer-products-more-durable-and-easier-to-repair

Good article: www.androidauthority.com/device-repairability-807585/ (archive).

Agriculture is not the official definition of the age. But it is good enough. Likely related to the official end of glaciations thing.

Like Jimmy Wales, he used to work in finance and then quit. What is it with those successful e-learning people??

The more of their syntax gets merged into mainline Cascading Style Sheets, the better the world will be.

We can almost reach the Lie algebra of any isometry group in a single go. For every $X$ in the Lie algebra we must have:because $e^{tX}$ has to be in the isometry group by definition as shown at Section "Lie algebra of a matrix Lie group".

Then:so we reach:With this relation, we can easily determine the Lie algebra of common isometries:

Bibliography:

For this sub-case, we can define the Lie algebra of a Lie group $G$ as the set of all matrices $M\in G$ such that for all $t\in \mathbb{R}$:If we fix a given $M$ and vary $t$, we obtain a subgroup of $G$. This type of subgroup is known as a one parameter subgroup.

The immediate question is then if every element of $G$ can be reached in a unique way (i.e. is the exponential map a bijection). By looking at the matrix logarithm however we conclude that this is not the case for real matrices, but it is for complex matrices.

Examples:

TODO example it can be seen that the Lie algebra is not closed matrix multiplication, even though the corresponding group is by definition. But it is closed under the Lie bracket operation.

TODO there was one which was relly good, can't find it anymore. One day.

Subtle is the Lord by Abraham Pais (1982) chapter 4 "Entropy and Probability" mentions well how Boltzmann first thought that the second law was an actual base physical law of the universe while he was calculating numerical stuff for it, including as late as 1872.

But then he saw an argument by Johann Joseph Loschmidt that given the time reversibility of classical mechanics, and because they were thinking of atoms as classical balls as in the kinetic theory of gases, then there always exist a valid physical state where entropy decreases, by just reversing the direction of time and all particle speeds.

So from this he understood that the second law can only be probabilistic, and not a fundamental law of physics, which he published clearly in 1877.

The term is not very clear, as it could either mean:

We define it as a linear map where the domain is the same as the image, i.e. an endofunction.

Examples:

This is the standard model.