Lorentz transformations from reflections: Some applications

We point out, by exhibiting two examples and mentioning a third one, that it,:is sometimes useful to consider Lorentz transformations as generated from hyperplane or line reflections. One example concerns the construction of boosts linking two given 4 vectors, the other one concerns the Minkowski geometric understanding of V. Moretti's polar decomposition of orthochronous Lorentz matrices.