Campoamor Stursberg, Otto-Rudwig2023-06-202023-06-2020081751-811310.1088/1751-8113/41/36/365207https://hdl.handle.net/20.500.14352/50617It is shown that for inhomogeneous Lie algebras having only one Casimir operator, the latter can be explicitly constructed from the Maurer-Cartan equations by means of wedge products. It is further proved that this constraint imposes sharp bounds for the dimension of the representation R defining the semidirect product. The procedure is generalized to compute also the rational invariant of some Lie algebrasengjournal articlehttps//doi.org/10.1088/1751-8113/41/36/365207http://iopscience.iop.org/1751-8121/41/36/365207/open access512.554.3Lie algebraCasimir operatorÁlgebra1201 Álgebra