• Eliana Lorch and Joshua Tan, The behavioral approach to systems theory, 15 June 2018.

Eliana Lorch is a mathematician based in San Francisco. Joshua Tan is a grad student in computer science at the University of Oxford and one of the organizers of Applied Category Theory 2018.

They wrote a great summary of this paper, which has been an inspiration to me and many others:

• Jan Willems, The behavioral approach to open and interconnected systems, *IEEE Control Systems* **27** (2007), 46–99.

• Maru Sarazola, Dynamical systems and their steady states, 2 April 2018.

She compares two papers:

• David Spivak, The steady states of coupled dynamical systems compose according to matrix arithmetic.

• John Baez and Blake Pollard, A compositional framework for reaction networks, *Reviews in Mathematical Physics* **29** (2017), 1750028.

(Blog article here.)

• Maru Sarazola, Dynamical systems and their steady states, 2 April 2018.

She compares two papers:

• David Spivak, The steady states of coupled dynamical systems compose according to matrix arithmetic.

• John Baez and Blake Pollard, A compositional framework for reaction networks, *Reviews in Mathematical Physics* **29** (2017), 1750028.

(Blog article here.)

• Tai-Danae Bradley and Brad Theilman, Cognition, convexity and category theory, The *n*-Category Café, 10 March 2018.

Any spinning massive object with its angular momentum pointing in the direction of its velocity will look like its angular momentum is pointing in the opposite direction of its velocity if you run faster than it.

As said I have an uneasyness with this picture, in particular this picture assumes somewhat that there exists a “neutrino charge” which behaves according to some kind of (hidden) Maxwells equations but even if one would accept this assumption for the moment then as the Wikipedia article says if an observer is faster the particle appears to move backwards, that would actually mean that the helicity would stay the same, because angular momentum (and therefore magnetic moment) AND relative velocity switch sign. But then in electrodynamics electrical and magnetic fields change when changing the frame and I have no idea what this does to the whole picture. And then one gets already for the electron an anomalous magnetic moment, if one takes quantum effects into acount, who knows what this is for the neutrino?

I doubt there’s a paper on this; there would only be a paper if someone discovered it wasn’t true.

Why? I don’t know how difficult it is to measure a neutrino’s spin or hellicity, but such an experiment could eventually say something about wether a neutrino needs to have a mass or not.

]]>Are there experiments, where this has been tested?

Any spinning massive object with its angular momentum pointing in the direction of its velocity will look like its angular momentum is pointing in the opposite direction of its velocity if you run faster than it. It’s easy to test this for large objects, a bit harder for small objects… but someone must have done it for electrons. I doubt there’s a paper on this; there would only be a paper if someone discovered it *wasn’t* true. This would be an immensely shocking discovery!