Symplectic group Updated 2025-07-16
Intuition, please? Example? mathoverflow.net/questions/278641/intuition-for-symplectic-groups The key motivation seems to be related to Hamiltonian mechanics. The two arguments of the bilinear form correspond to each set of variables in Hamiltonian mechanics: the generalized positions and generalized momentums, which appear in the same number each.
Seems to be set of matrices that preserve a skew-symmetric bilinear form, which is comparable to the orthogonal group, which preserves a symmetric bilinear form. More precisely, the orthogonal group has:
and its generalization the indefinite orthogonal group has:
where S is symmetric. So for the symplectic group we have matrices Y such as:
where A is antisymmetric. This is explained at: www.ucl.ac.uk/~ucahad0/7302_handout_13.pdf They also explain there that unlike as in the analogous orthogonal group, that definition ends up excluding determinant -1 automatically.
Therefore, just like the special orthogonal group, the symplectic group is also a subgroup of the special linear group.
The best films of all time Updated 2025-07-16
There is only a very fine difference between a very good film, and the best films of all time. Perhaps it is something to do on how epic the subject matter is? It is often very hard to tell, and switches between the categories are also possible.
Chinese traditional painting Updated 2025-07-16
Unclear legality:
Chomsky hierarchy Updated 2025-07-16
This is the classic result of formal language theory, but there is too much slack between context free and context sensitive, which is PSPACE (larger than NP!).
A good summary table that opens up each category much more can be seen e.g. at the bottom of en.wikipedia.org/wiki/Automata_theory under the summary thingy at the bottom entitled "Automata theory: formal languages and formal grammars".
Super Mario 64 Updated 2025-07-16
And as a result, adult Ciro really enjoys tool-assisted speedruns of the game.
The Man From Earth (2007) Updated 2025-07-16
Good theory of Jesus.
List of similar feeling films: www.youtube.com/watch?v=zwYwFoanrNg 11 Underrated Hard Sci-fi Movies by Marvelous Videos (2021)
TwinsUK Updated 2025-07-16
Church of England Updated 2025-07-16
Political division:
  • nominal leader: British monarch
  • toplevel arch-dioceses/provinces of Cantebury and York. One archbishop each, who is also bishop of Cantebury and York diocese
  • within provinces: one cathedral and bishop per diocese
Chu (state) Updated 2025-07-16
Slow neutron Updated 2025-07-16
Tangent space Updated 2025-07-16
TODO what's the point of it.
Bibliography:
Tax the rich Updated 2025-07-16
Video 1.
How the rich avoid paying taxes by Vox (2021)
Source. Features interview with Morris Pearl, a rich dude that is campaigning to tax the rich. He also participates in an association called "Patriotic Millionaires" to further this agenda.
Video 2.
What Eating the Rich Did For Japan by Asianometry (2021)
Source.
Domain hack Updated 2025-07-16
Some cool ones:
  • playinside.me
eLife Updated 2025-07-16

There are unlisted articles, also show them or only show them.