409 karma · joined July 16, 2020
[1]: https://www.bmtdynamics.org/cgi-bin/display.pl?name=rdaic
[2]: https://books.google.fr/books?id=2zDUCQAAQBAJ
[3]: https://en.wikipedia.org/wiki/Taylor%27s_theorem#Taylor's_th...
(1+e1)*(1+e2) = 1+e1+e2+(e1*e2)
If e1 and e2 are small, then e1*e2 is negligible.
He notably did convincing calculations showing that the sun should be larger than Earth. However, this was not convincing enough for his opponents who argued notably that usually fire hardly remains in a fixed position. Also, if Earth was moving, it was hard to understand why there was no observed parallax on the stars at night. Actually, the first apparent proof that Earth was moving came after inventing instruments precise enough to observe parallax on far enough stars, in 1727, from James Bradley. It actually had different results from expectation, due to the finite speed of light [1].
Just after Aristarchus came also Seleucus of Seleucia [2]. He supposedly had a theoretical argument for heliocentrism, but it was lost.
[0]: https://en.wikipedia.org/wiki/On_the_Sizes_and_Distances_(Ar...
Transmission congestion might be a more important issue than profitability: "Avoiding the congestion is essential for a competitive electricity market and is one of the toughest problems of its design." [1]
The course of Damien Ernst [2] gives an excellent overview of all the challenges related to decentralized electricity markets.
[1]: https://en.wikipedia.org/wiki/Transmission_congestion
[2]: https://damien-ernst.be/teaching/elec0018-1-energy-markets/
This makes me think of wood dust being dangerous to inhale [1], despite wood being a perfectly safe material for furniture at home.
[1]: https://en.wikipedia.org/wiki/Health_impacts_of_sawdust
The full school institution actually do it. Teachers tell students to stop speaking to each others for most courses during the week. Moreover some teachers explicitly talk about the joy of quietly reading books, and directly ask students to do so.
I'm fine with the way school works, especially considering the limited resources they have. Nevertheless, teachers do not often encourage extroverted skills that are useful in group work, oral presentations, etc. Exams seem to favor people that are able to stay hours long alone thinking about abstract concepts.
f: a function indicating how complete the thoughts are.
A: writing about thoughts.
The correct statement from a logical point of view is: if A implies B, then not B implies not A.
In this case, even if writing down your ideas makes them more precise, there might be other methods that make your ideas more precise. Again this is just the logical point of view, out of context.
[1]: https://github.com/CLAY-3D/OpenCLAY
[1]: https://en.wikipedia.org/wiki/Remez_algorithm
[2] : https://www.sollya.org/
Note that through this mechanism, the society is still a control society [2], even though citizen themselves have more to say in that control.
It is even theoretically possible to embed the flat paper as a torus in 3D with a C^1 surface, without polyhedral edges [2,3]. However, this surface has a fractal structure.
Finally, any torus surface embedded in 3D that is at least C^2 (with a continuous second derivative) will nessecarily stretch some distances [4].
[1]: https://www.imaginary.org/hands-on/diplotori-flat-polyhedral...
[2]: https://aperiodical.com/2012/05/torus/
[3]: https://www.pnas.org/doi/full/10.1073/pnas.1118478109
[4]: https://math.stackexchange.com/questions/2291382/c2-isometri...
And researchers from Google Deepmind, University of Wisconsin-Madison and Laboratoire de l’Informatique du Parallélisme, University of Lyon, actually publish some of their results in that direction [1,2].
[1]: https://deepmind.google/discover/blog/funsearch-making-new-d...
On the other hand, even in academy, scientific articles are not always the best examples of open and reproducible research [2,3]. And in computer science, it is common for articles to be more focused on algorithms than on implementations.
[1]: https://deepmind.google/impact/meet-the-scientists-using-alp...
The mass being different, this leads to different forces required to get the same acceleration or deceleration. That follows directly from the formula: force = mass * acceleration.
Moreover, the resonance frequency [1] of an object is different for different scales. For example, piano strings will vibrate at different speeds, depending on their sizes. That would be the same for the robot cables.
Also, when changing the scale of an object, the materials often change. The cables and the motors would probably be built differently, with different physical properties.
In general, to design a new mechanism, it is common practice to start with software simulations, 3D prints, and small scale prototypes. However, the properties of the new mechanism are only validated when you have built a real size prototype.
An employee of an animation company describes in a comic book his experience on working with people drawing the in-between frames. They were paid literally with rice bags [1].
[1]: https://en.wikipedia.org/wiki/Pyongyang:_A_Journey_in_North_...
If you didn't buy the song, does it count as an illegal recording? /s
This was the main subject of a science fiction short story, unfortunately I cannot remember its title or author.
An example of wrong proof due to sketching quickly some cases is the proof that all triangles are isosceles [1].
Here is also an example of an apparently obvious result with a non-trivial proof, were all the cases are written out formally in the proof-assistant language Coq [2]. It is the proof that if we compute the multiplications and the square roots with floating-point arithmetic in base 2, then sqrt(a*a) is actually |a|. This was assumed without proof in some previous papers, and it is easy to understand how the authors may have missed it. Note that this result is not true in base 10.
Finally, sometimes non-formal proof can actually be more convincing than formal proof. For example, it was proven formally in 1957 that it is possible to turn a sphere inside out continuously, without cutting it, tearing it or creating any crease [3]. With more work, this result was later proven with a video. The video proof is arguably easier to follow and more convincing for a human. The formal proof has not yet been formally checked by a proof assistant, although work in this direction is on the way [4].
[1]: https://www.themathdoctors.org/false-proofs-geometry/
[2]: https://inria.hal.science/hal-01148409v1/document