Dear all ginac lovers, I have found simplify_indexed() is not working as expected. I have compiled and run the following c++ program using ginac 1.87 (mingw64 compiler, windows 10 os), #include <ginac/ginac.h> using namespace GiNaC; using namespace std; int main() { symbol A("A"), B("B"), C("C"), i_sym("i"),j_sym("j"); varidx i(i_sym, 3); varidx ic(i_sym, 3,true); varidx j(j_sym, 3); varidx jc(j_sym, 3,true); ex e = indexed(A, {i,i}) * indexed(B, {ic,ic})-indexed(A, {j,j}) * indexed(B, {jc,jc}); cout << (e).simplify_indexed() << endl; return 0; } the above program shows the following result: A.i.i*B~symbol16.symbol16-A.i.i*B~symbol17.symbol17 But I think the result should be zero. Please tell me what is the problem here? Best regards, Mithun Bairagi