need help with physics homework

If you were wondering what is the officially approved metric for the solar system :

iopscience.iop.org/article/10.1086/378162

Is there any difference between a Markov chain and a directed weighted graph?

@DanielUnderwood Not really, I think - just that the weights in a Markov chain obviously have constraints on them that a generic weighted graph doesn't

Can't all be zero for a start

or negative, really

The non-trivial constraint I was thinking of was "the weights of all outgoing edges of a node must sum to 1"

well if they're not that's fine as long as you normalize the probability

that's how a lot of them work in practice

yeah that's the only difference I could think of

I guess it's fine even not normalizing them if you just look at a single state at a time, but it seems like you may need the normalization to build a transition matrix if you want to evolve that way

@PM2Ring ping (as discussed) I think it would be great if you added an answer there! I'm not keen on learning how to write Jupyter notebooks and will appreciate an alternative.

@uhoh Sorry, I don't have an account on Academia.SE. You can use Matplotlib in Sage, but for 3D stuff, it's probably cleaner & simpler to use Sage's own 3D facilities. It provides a few 3D rendering engines; I normally use the default one, which is based on three.js.

The nice thing about running scripts on SageMathCell is that the entire script is encoded into the query string of the URL (using zlib compression & base64 encoding). Admittedly, that does make the script dependent on a SageMathCell server. OTOH, I doubt that Sage will disappear anytime soon. And the script can easily be run on any server that has Sage & SageMathCell installed, you just need to change the address part of the URL before the query string.

Hi everyone!

Hope find you all safe, well and healthy.

is $SU(2) = SU(2)_{Left} \times SU(2)_{Right}?

$SU(2) = SU(2)_{Left} \times SU(2)_{Right}$?

no

usually people subscript a group like $\mathrm{SU}(2)$ if there is more than one copy of $\mathrm{SU}(2)$ acting on the theory

so what is, in classical field theory and QFT, the $SU(2)\times SU(2)$?

impossible to say, there isn't any general meaning to writing $\mathrm{SU}(2)_\text{Left}$, you have to define what you mean by that in the specific context

what specific groups you have is a function of your action (i.e. what it is symmetric under), not a general property of field theory as such

I see...well, I will keep studying then. Thanks!