  It is proposed the algorithm that find a basis of the ideal and a basis of
the space of all root functionals by using the extension operation for bounded
root functionals, when the number of polynomials is equal to the number of
variables, if it is known that the ideal of polynomials is 0-dimensional. The
asyptotic complexity of this algorithm is d^{O(n)} operations, where n is the
number of polynomials and the number of variables, d is the maximal degree of
polynomials. The extension operation has connection with the multivariate
Bezoutian construction.
