Nonunimodular Lorentzian flat Lie algebras

Mohamed Boucetta, Hicham Lebzioui

A Lorentzian flat Lie group is a Lie group $G$ with a flat left invariant metric $\mu$ with signature $(1,n-1)=(-,+,\dots ,+)$. The Lie algebra $\mathfrak{g}=T_{e}G$ of $G$ endowed wit…