Quaternion Updated 2025-07-16
Kind of extends the complex numbers.
Some facts that make them stand out:
DNA Updated 2025-07-16
Since DNA is the centerpiece of life, Ciro Santilli is extremely excited about DNA-related technologies, see also: molecular biology technologies.
Hexagon Updated 2025-07-16
Matrix multiplication Updated 2025-07-16
Since a matrix can be seen as a linear map , the product of two matrices can be seen as the composition of two linear maps:
One cool thing about linear functions is that we can easily pre-calculate this product only once to obtain a new matrix, and so we don't have to do both multiplications separately each time.
Potassium Updated 2025-07-16
Huainanzi Updated 2025-07-16
Spin number of a field Updated 2025-07-16
Physics from Symmetry by Jakob Schwichtenberg (2015) chapter 3.9 "Elementary particles" has an amazing summary of the preceding chapters the spin value has a relation to the representations of the Lorentz group, which encodes the spacetime symmetry that each particle observes. These symmetries can be characterized by small integer numbers:
As usual, we don't know why there aren't elementary particles with other spins, as we could construct them.
Emotion Updated 2025-07-16
A detailed list of all transactions is kept at: ../sponsor/budget.js.
Ciro Santilli use the following accounting for this sponsorship calculations.
For significant one time donations, he takes the final money received in one of his cash GBP accounts, then he checks how much that is in dollars on Google at the time of cash out, and then writes that amount down as the final dollar value which is what ultimately counts. This exposes Ciro to USD/GBP fluctuations, but it simplifies accounting for donors which is more important, so it is likely worth it.
For small regular donations, Ciro just tallies it all up in GBP from time to time and converts it all to dollars in one go as it is not worth spending too much time updating those too often.
Flagellum Updated 2025-07-16
Focal length Updated 2025-07-16
If you pass parallel light.
For a biconvex spherical lens, it is given by:
where:
  • n: f nidnex
Football Updated 2025-07-16
Football is a synonym for association football, can we be done with that! The word "soccer" is an aberration.

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