This is a procedure performs Gröbner basis computation using the
package selected by desingcfg[gblib].
At least one of the blocks must contain a variable and then the
defined ordering is the block degree-reverse-lexicographic one with
B1-variables being bigger than B2-ones.
- a list of polynomials in the variables [op(B1),op(B2)],
- the first block of variables of the ordering
- the second block of variables of the ordering
- A list of polynomials forming a Gröbner basis for the
input with respect to the given ordering.