Ringel's contributions to quasi-hereditary algebras

Quasi-hereditary algebras were introduced by Cline, Parshall and Scott to describe the highest weight categories of representations of semisimple Lie algebras and algebraic groups by the module categories of finite-dimensional algebras. Since then a lot of homological, structural and categorical properties of quasi-hereditary algebras have been discovered. This class of algebras seems quite common and occurs in many branches of mathematics. There are lots of important works on the subject. In this note we mainly survey some of Claus Michael Ringel's works or works jointly with his collaborators on quasi-hereditary algebras. Also, some of related works and recent developments on quasi-hereditary algebras are mentioned.