algebraic classification of the isometry-isotropy pairs of four-dimensional pseudo-
Riemannian metrics admitting local slices with five-dimensional isometries contained in the
Lorentz algebra. A purely Lie algebraic approach is applied with emphasis on the use of Lie
theoretic invariants to distinguish invariant algebra-subalgebra pairs. This method yields an
algorithm for identifying isometry-isotropy pairs subject to the aforementioned constraints.