Bulletin of the
Korean Mathematical Society BKMS

We provide the set of left-invariant minimal unit vector fields on the semi-direct product $\mathbb R^n\rtimes_P\mathbb R$, where $P$ is a nonsingular diagonal matrix and on the 7 classes of 4-dimensional solvable Lie groups of the form $\mathbb R^3\rtimes_P\mathbb R$which are unimodular and of type $(R)$.

Keywords: left-invariant minimal unit vector field, Lie group, semi-direct product

MSC numbers: 53C20, 53C25, 53C42