
Gauss's Principle of Least Constraint (2017) - vectorrain
http://preetum.nakkiran.org/misc/gauss/
======
ars
This reminds me of the rule in particle physics: Anything not forbidden is
mandatory.

i.e. There are no events (interactions) that could happen, but just don't.

[https://en.wikipedia.org/wiki/Totalitarian_principle](https://en.wikipedia.org/wiki/Totalitarian_principle)

~~~
seiferteric
Very cool, I wonder if this applies to interactions that "can't" happen in our
current universe? I have read in the early big bang, forces "combined"
together, like the electric and nuclear weak force. Could a electron interact
with a neutrino for example?

~~~
raattgift
> Could a electron interact with a neutrino for example

Could, and it does happen. Observed about sixteen years after the first direct
observation of a neutrino interaction:

[https://www.worldscientific.com/doi/abs/10.1142/S02177323930...](https://www.worldscientific.com/doi/abs/10.1142/S0217732393002567)
(PDF directly at
[https://cds.cern.ch/record/248487/files/ppe-93-065.pdf](https://cds.cern.ch/record/248487/files/ppe-93-065.pdf)
)

More modernly and generally, neutrino-lepton scatterings are part of the weak
interactions in the Standard Model:
[https://www2.ph.ed.ac.uk/~playfer/PPlect11.pdf](https://www2.ph.ed.ac.uk/~playfer/PPlect11.pdf)

(and of course there is an even weaker gravitational interaction between
leptons and neutrinos that we cannot demonstrate directly with current
technology)

------
pvitz
By looking at the references, the author may not be aware of the use of Gauss'
principle in molecular dynamics, see e.g. Ch. 3.1 in Evans, Morriss:
Statistical mechanics of nonequilibrium liquids.
([http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.296...](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.296.2041&rep=rep1&type=pdf))

------
ouid
their double pendulum applet has a bug that occasionally causes it to gain
energy.

