# Sub-manifold: bug or my misunderstanding?

### Define a manifold and sub-manifold:

R2 = Manifold(2, 'R^2', start_index=1) # R^2

c_xy.<x,y> = R2.chart() # Cartesian coordinates on R^2

M = R2.open_subset('M', coord_def={c_xy: x>0 and y>0}) # First quadrant

### Test the coordinate restrictions:

R2.point((0,1)) in M; R2.point((0,0)) in M; R2.point((1,0)) in M; R2.point((1,1)) in M

### Result:

False
False
*True*
True

Question: Have I misunderstood how to restrict to the first quadrant, or have I stumbled on a bug?