// create two size n vectors of symbols, one for the coefficients
// a[0],..,a[n], one for indeterminates x[0]..x[n]:
vector<symbol> a;
vector<symbol> x;
for (unsigned i=0; i<n; ++i) {
// create two size n vectors of symbols, one for the coefficients
// a[0],..,a[n], one for indeterminates x[0]..x[n]:
vector<symbol> a;
vector<symbol> x;
for (unsigned i=0; i<n; ++i) {