The fglm command computes the reduced lexicographic Groebner basis from a grevlex basis A in the variables X modulo P. The system must have a finite number of solutions, that is, its hilbert dimension must be zero. Progress information is available by setting info().
sys = [x^2+y, x*y-1]; G = groebnerbasis(sys,[x,y],[],0); fglm(G,[x,y],0); [1+y^3, x+y^2]