1 | initial version |

Yes, there is a more elegant way:

```
A = G(g(R1((1,))))
B = G(g(R1((0,))))
```

Explanations: `R1((1,))`

is the point of coordinate `t=1`

on the manifold `R1`

, `g(R1((1,)))`

is the image of this point by the map `g`

; by the very definition of `g`

, this is a point of `R3`

and finally, `G(g(R1((1,))))`

is the image by `G`

of this last point.

Even better, if instead of declaring `R1`

as a manifold of dimension 1, you declare it as the real line manifold via `RealLine`

(see this documentation), i.e. if you replace the two lines

```
R1 = Manifold(1, 'R1', start_index=1, latex_name=r'\mathbb{R}')
cartesian1d.<t> = R1.chart()
```

by the following single one:

```
R1.<t> = RealLine()
```

then you can use directly the notation `g(1)`

instead of `g(R1((1,)))`

:

```
A = G(g(1))
B = G(g(0))
```

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