[PPL-devel] Set of C_Polyhedron

Hello, I am writing a program that requires a huge set of C_Polyhedrons. I have tried making a set<C_Polyhedron> which g++ does not object to, but when I try to insert a C_Polyhedron into it, g++ throws an error about not being able to compare C_Polyhedrons. Is there a way to make a set of C_Polyhedrons? If it is not possible, is it practical to make a set of strings, where the strings are the C_Polyhedron's corresponding Generator_Systems, and use that set? Thank you so much for your help, Jeff