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.
The Purpose of Harvard is Not to Educate People by Sean Carroll (2008) Updated 2025-07-16
Maybe they did try once though: Harvard Project Physics.
Chinese traditional music Updated 2025-07-16
The best instrumental songs: Section "The best Chinese traditional instrumental music"
In the process of moving out of: cirosantilli.com/china-dictatorship/music
Bibliography:
- Ciro Santilli's YouTube playlist: www.youtube.com/playlist?list=PLcZOZrP1P_V5J2P3ogZNpya0BAuPEgyuE
- Reddit:
- www.reddit.com/r/classicalmusic/comments/op54d5/traditional_chinese_music_recommendations_helpful/ "Traditional Chinese Music Recommendations & Helpful Sources" by
_AsyA_(2021). This user knows a bit as shown in description. - www.reddit.com/r/China/comments/1ejy8jw/how_to_get_into_traditionalclassical_chinese_music/ "How to get into traditional/classical chinese music?" by Ultimate_CockSucker (2024)
- www.reddit.com/r/Chinese/comments/150sf4y/what_are_some_really_good_traditional_chinese/ "What are some really good Traditional Chinese music artists?" by Flimsy-Assumption513 (2023)
- www.reddit.com/r/classicalmusic/comments/op54d5/traditional_chinese_music_recommendations_helpful/ "Traditional Chinese Music Recommendations & Helpful Sources" by
Chinese traditional painting Updated 2025-07-16
Some free online collections:
** collections.si.edu/search/results.htm?q=&fq=online_visual_material%3Atrue&fq=online_media_type%3A%22Images%22&fq=culture%3A%22Chinese%22&fq=object_type%3A%22Paintings%22&view=list&date.slider=300s%2C1800s
Unclear legality:
- www.ibiblio.org/chinese-music/html/traditional.html has many tracks which appear to be rips from vinyl records due to the scratching sound, and unclear attribution
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!).
By Noam Chomsky.
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".
Christian denomination Updated 2025-07-16
Super Mario 64 Updated 2025-07-16
Ah, Ciro Santilli loved this one... games young Ciro Santilli played.
Super Mario Bros. Updated 2025-07-16
The Man From Earth (2007) Updated 2025-07-16
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
New Testament part Updated 2025-07-16
Slow neutron Updated 2025-07-16
Tangent space Updated 2025-07-16
Bibliography:
- www.youtube.com/watch?v=j1PAxNKB_Zc Manifolds #6 - Tangent Space (Detail) by WHYB maths (2020). This is worth looking into.
- www.youtube.com/watch?v=oxB4aH8h5j4 actually gives a more concrete example. Basically, the vectors are defined by saying "we are doing the Directional derivative of any function along this direction".One thing to remember is that of course, the most convenient way to define a function and to specify a direction, is by using one of the coordinate charts.
- jakobschwichtenberg.com/lie-algebra-able-describe-group/ by Jakob Schwichtenberg
- math.stackexchange.com/questions/1388144/what-exactly-is-a-tangent-vector/2714944 What exactly is a tangent vector? on Stack Exchange
Tax the rich Updated 2025-07-16
Basic Linear Algebra Subprograms Updated 2025-07-16
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.