Algebraic geometry Algebraic groups {For linear algebraic groups, see 20Gxx; for Lie algebras, see 17B45} Buildings (Group theory) Buildings and the geometry of diagrams Categories (Mathematics) Categorías (Matemáticas) Category theory; homological algebra {For commutative rings see 13Dxx, for associative rings 16Exx, for groups 20Jxx, for topological groups and related structures 57Txx; see also 55Nxx and 55Uxx for Catégories (Mathématiques) Filters (Mathematics) Filtres (Mathématiques) Finite geometry and special incidence structures Geometry {For algebraic geometry, see 14-XX} Group schemes Group schemes (Mathematics) Group theory and generalizations Groups with a $BN$-pair; buildings [See also 51E24] Immeubles (Théorie des groupes) Linear algebraic groups and related topics {For arithmetic theory, see 11E57, 11H56; for geometric theory, see 14Lxx, 22Exx; for other methods in representation the Monoids Monoïdes Schémas en groupes Structure and classification of infinite or finite groups Teoría de grupos