`desing/pder`
Performing partial differentiation w.r.t. the parameter system of a
chart.
- Input:
-
- S
- a list of variables,
- f
- a polynomial from k[S],
- p
- an index to the IND member of the chart,
- PDER
- a list of lists of polynomials (the corresponding member
of the chart).
- Output:
- the partial derivative of f w.r.t.
IND[p].