Given a Lie algebra $\mathfrak{g}$, then a *Casimir element* or *Casimir invariant* is an element in the center of its universal enveloping algebra $U(\mathfrak{g})$.

Often this is considered with some Lie algebra representation in mind, in which case one speaks of *Casimir operators*.

Named after Hendrik Casimir, who discovered the concept in the context of rigid body dynamics.

- Wikipedia,
*Casimir element*

Last revised on March 31, 2021 at 23:22:41. See the history of this page for a list of all contributions to it.