Hello! This simple program #include <iostream> #include <ginac/ginac.h> using namespace std; using namespace GiNaC; int main(int argc, char** argv) { symbol x("x"); symbol a("a"); symbol b("b"); ex test = pow(x+a,b); cout << test << " = " << test.series(x,3) << endl; return 0; } gives (x+a)^b = 1+Order(x^3) instead of (x+a)^b = (a^b)+(a^b*b*a^(-1))*x+(1/2*a^b*b^2*a^(-2)-1/2*a^b*b*a^(-2))*x^2+Order(x^3) Attached patch fix this bug.