Hi! Note that the following program fails to compute decomp_rational(pow(x,-2),x) #include <iostream> #include <ginac/ginac.h> using namespace std; using namespace GiNaC; int main() { symbol x("x"); cout << "r="<<decomp_rational(pow(x,-2),x) << endl; return 0; } while for decomp_rational(pow(x,-1),x) it succeeds. Any ideas why decomp_rational fails in the previous case, in fact, it seems to fail for all n>1 in x**-n. I am using latest GiNaC from CVS on woody debian. Regards, Pearu