Lie algebra representation
In the mathematical field of representation theory, a Lie algebra representation or representation of a Lie algebra is a way of writing a Lie algebra as a set of matrices (or endomorphisms of a vector space) in such a way that the Lie bracket is given by the commutator. In the language of physics, one looks for a vector space V {\displaystyle V} together with a collection of operators on V {\displaystyle V} satisfying some fixed set of commutation relations, such as the relations satisfied by the angular momentum operators.
Source: Wikipedia — Lie algebra representation (CC BY-SA 4.0)