Hi,

In DG methods, we set a quadrilateral mesh like this:

```
mesh = ngm.MakeStructured2DMesh(quads=True, nx=10, ny=10)
V = VectorL2(mesh, order=3, dgjumps=True)
```

In fact, we want to add some vector basis to the vector space V. So it is essential to know how the vector basis is composited in V. I guess it hides in one core documents but cannot find it.

Best,

Di Yang