# Contents

## Definition

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.

## References

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

Created on January 9, 2017 at 09:28:18. See the history of this page for a list of all contributions to it.