Dear GiNaC developers, This is Hidehiro Fujio of NEC Corp. Japan. At first, I would like to say thank you very much for your significant contribution to the formula manipulation area by GiNaC library in the world, and I also have to say that thank you very much for your link to my small document in the Related Software page. (My system is feelfem, an FEM code generator.) Yesterday, I met my supervisor, and got his advice. I wll expand my feelfem system to deal with 3D Maxwell equation, and introduce the differential operator 'rot' and 'div' and 'grad' (rotation, divergence, gradient, respectively), and my professors suggestion is it may be possible to expand these differential operators into just a set of basic differential operators (like dx,dy,dz) inside GiNaC. I would like to investigate your documentation agaian, and I would like to make a reort, how to make an FEM code generator by GiNaC. Again, thank you very much for GiNaC. And I'm afraid it is not an appropriate mail............ Best regards, Hidehiro Fujio # mail to both ( h-fujio@ab.jp.nec.com , oimo@world.email.ne.jp ,if needed)