12-00 General reference works (handbooks, dictionaries, bibliographies, etc.)
12-01 Instructional exposition (textbooks, tutorial papers, etc.)
12-02 Research exposition (monographs, survey articles)
12-03 Historical (must also be assigned at least one classification number from Section 01)
12-04 Explicit machine computation and programs (not the theory of computation or programming)
12-06 Proceedings, conferences, collections, etc.
12Dxx Real and complex fields
12Exx General field theory
12Fxx Field extensions
12Gxx Homological methods (field theory)
12Hxx Differential and difference algebra
12Jxx Topological fields
12Kxx Generalizations of fields
12Lxx Connections with logic
12Y05 Computational aspects of field theory and polynomials