81-00 General reference works (handbooks, dictionaries, bibliographies, etc.)
81-01 Instructional exposition (textbooks, tutorial papers, etc.)
81-02 Research exposition (monographs, survey articles)
81-03 Historical (must also be assigned at least one classification number from Section 01)
81-04 Explicit machine computation and programs (not the theory of computation or programming)
81-05 Experimental papers
81-06 Proceedings, conferences, collections, etc.
81-08 Computational methods
81Pxx Axiomatics, foundations, philosophy
81Qxx General mathematical topics and methods in quantum theory
81Rxx Groups and algebras in quantum theory
81Sxx General quantum mechanics and problems of quantization
81Txx Quantum field theory; related classical field theories [See also 70Sxx]
81Uxx Scattering theory [See also 34A55, 34L25, 34L40, 35P25, 47A40]
81Vxx Applications to specific physical systems