1900  General reference works (handbooks, dictionaries, bibliographies, etc.)


1901  Instructional exposition (textbooks, tutorial papers, etc.)


1902  Research exposition (monographs, survey articles)


1903  Historical (must also be assigned at least one classification number from Section 01)


1904  Explicit machine computation and programs (not the theory of computation or programming)


1906  Proceedings, conferences, collections, etc.



19Axx  Grothendieck groups and $K_0$ [See also 13D15, 18F30]

19Bxx  Whitehead groups and $K_1$

19Cxx  Steinberg groups and $K_2$

19Dxx  Higher algebraic $K$theory

19Exx  $K$theory in geometry

19Fxx  $K$theory in number theory [See also 11R70, 11S70]

19Gxx  $K$theory of forms [See also 11Exx]

19Jxx  Obstructions from topology

19Kxx  $K$theory and operator algebras [See mainly 46L80, and also 46M20]

19Lxx  Topological $K$theory [See also 55N15, 55R50, 55S25]

19M05  Miscellaneous applications of $K$theory

