Let a hypothetical one-dimensional world consist of a ray with...
values x>=0. This world is completely empty except for a mass
point with unit mass 1 at x=1. This is described by a "mass
density" R(x), which is zero everywhere except for R(1)=1.
[[Mod. note -- In order to have unit mass, doesn't your mass density
need to be a Dirac delta-function? -- jt]]
To better understand symmetries, I have a few questions, but for
simplicity's sake I'll start with one:
ram@zedat.fu-berlin.de (Stefan Ram) writes:
To better understand symmetries, I have a few questions, but for >>simplicity's sake I'll start with one:
And here's my other question:
It's about something I often encounter in texts about
symmetries, the point where I find it hard to follow.
Here's an example:
|Given a perfect circle, you can rotate it by a tiny amount
|and find that you still have the same circle.
"Why String Theory?" (2016) - Joseph Conlon (1981/)
. A kinematic "rotation", to me, is a change in the angular
position of an object. I think of a "circle" as a physical object,
Now a scientist comes along and says: I formally extend this world
to a two-dimensional world with the coordinates (x,y).
Sysop: | Keyop |
---|---|
Location: | Huddersfield, West Yorkshire, UK |
Users: | 342 |
Nodes: | 16 (2 / 14) |
Uptime: | 28:19:47 |
Calls: | 7,513 |
Calls today: | 10 |
Files: | 12,713 |
Messages: | 5,641,937 |
Posted today: | 2 |