Campoamor Stursberg, Otto-Rudwig2023-06-202023-06-2020070375-960110.1016/j.physleta.2006.10.050https://hdl.handle.net/20.500.14352/50673Contrary to the expected behavior, we show the existence of non-invertible deformations of Lie algebras which can generate invariants for the coadjoint representation, as well as delete cohomology with values in the trivial or adjoint module. A criterion to decide whether a given deformation is invertible or not is given in dependence of the Poincaré polynomial.engjournal articlehttps//doi.org/10.1016/j.physleta.2006.10.050http://www.sciencedirect.com/science/article/pii/S0375960106016422open access512Álgebra1201 Álgebra