representation theory

representation theory

[‚rep·ri‚zen′tā·shən ‚thē·ə·rē] (mathematics) The study of groups by the use of their representations. The determination of representations of specific groups. (quantum mechanics) Quantum-mechanical device in which one selects the common eigenfunctions of a complete set of quantum-mechanical operators as a basis of vectors in a Hilbert space, and expresses wave functions and operators in terms of column matrices and square matrices, respectively, which correspond to this basis.