## 20-XX GROUP THEORY AND GENERALIZATIONS

- 20-00 General reference works (handbooks, dictionaries, bibliographies, etc.)
- 20-01 Instructional exposition (textbooks, tutorial papers, etc.)
- 20-02 Research exposition (monographs, survey articles)
- 20-03 Historical (must also be assigned at least one classification number from Section 01)
- 20-04 Explicit machine computation and programs (not the theory of computation or programming)
- 20-06 Proceedings, conferences, collections, etc.
- 20Axx Foundations (1)
- 20Bxx Permutation groups
- 20Cxx Representation theory of groups [See also 19A22 (for representation rings and Burnside rings)] (3)
- 20Dxx Abstract finite groups
- 20Exx Structure and classification of infinite or finite groups
- 20Fxx Special aspects of infinite or finite groups
- 20Gxx Linear algebraic groups and related topics (For arithmetic theory, see 11E57, 11H56; for geometric theory, see 14Lxx, 22Exx; for other methods in representation theory, see 15A30, 22E45, 22E46, 22E47, 22E50, 22E55)
- 20Hxx Other groups of matrices [See also 15A30]
- 20Jxx Connections with homological algebra and category theory
- 20Kxx Abelian groups
- 20Lxx Groupoids (i.e. small categories in which all morphisms are isomorphisms) (For sets with a single binary operation, see 20N02; for topological groupoids, see 22A22, 58H05)
- 20Mxx Semigroups
- 20Nxx Other generalizations of groups
- 20Pxx Probabilistic methods in group theory [See also 60Bxx]