In general, Gröbner bases computations are of double-exponential worst-case complexity. So, this would make it impossible to apply them to your problems.
But, for a large amount of problem classes there exist more efficient algorithms. S
INGULARs
Code:
groebner
command uses a sophisticated heuristic of selecting appropriate subroutines. It might help, if one has some background information about the problem. In that case one can find an optimized routine, or even a good preprocessing.
About, calling Singular. The maximum number of variables in Singular is 32767. First you define a ring like this:
Code:
ring r = 0,x(1..32000),dp;
You may also name each variable:
Code:
ring r = 0,(x, y, a, b, w),dp;
For the polynomial system in question you write something like
Code:
ideal I = (a,b, x*y);
groebner(I);
Of course, for thousands of variables you should write everything in a file and call
Code:
Singular filename
from the command line.
Regards,
Alexander