Associative rings Representations of rings (Algebra) Algebraic geometry Algebraic groups Associative rings and algebras Auslander-Reiten sequences (almost split sequences) and Auslander-Reiten quivers Derivations, actions of Lie algebras Group actions on varieties or schemes (quotients) Group theory and generalizations Modular representations and characters Representation theory of groups Representation theory of rings and algebras Representation type (finite, tame, wild, etc.) Representations of Artinian rings Representations of quivers and partially ordered sets Rings and algebras with additional structure