Dear GiNaCers, I modified the functions that construct epsilon_tensors in tensor.cpp. They now test whether their arguments are wildcards. In that case these tensors remain unevaluated. The problem is that if one tries to use .find(epsilon_tensor(idx(wild(0),2),idx(wild(1),2))) this may get "simplified" into -epsilon_tensor(idx(wild(1),2),idx(wild(0),2)) thereby obstructing the find method. This change is in the same patch as I applied to CVS in order to revive the return_type_tinfo system. Best, Chris