1 | initial version |

Actually, you must declare the first quadrant as

```
M = R2.open_subset('M', coord_def={c_xy: [x>0, y>0]})
```

Then the output of your test is correct, i.e. it is False False *False* True.

Of course the syntax you used, i.e. `x>0 and y>0`

, is more user friendly, and we should definitively implement it! For the time being, coordinate conditions passed as a list are combined with `and`

, while those passed as a tuple are combined with `or`

. For instance `[x>0, (y>2, y<-2)]`

stands for `x>0 and (y>2 or y<-2)`

. This is documented in the function `add_restrictions`

on http://sagemanifolds.obspm.fr/doc/reference/manifolds/sage/manifolds/chart.html

2 | No.2 Revision |

Actually, you must declare the first quadrant as

```
M = R2.open_subset('M', coord_def={c_xy: [x>0, y>0]})
```

Then the output of your test is correct, i.e. it is False False *False* True.

Of course the syntax you used, i.e. `x>0 and y>0`

, is more user friendly, and we should definitively implement it! For the time being, coordinate conditions passed as a list are combined with `and`

, while those passed as a tuple are combined with `or`

. For instance `[x>0, (y>2, y<-2)]`

stands for `x>0 and (y>2 or y<-2)`

. This is documented in the function `add_restrictions`

on ~~http://sagemanifolds.obspm.fr/doc/reference/manifolds/sage/manifolds/chart.html~~http://sagemanifolds.obspm.fr/doc/reference/manifolds/sage/manifolds/chart.html, but not in the function `open_subset`

, as it should; sorry for the inconvenience.

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