  We investigate the Fermat-Torricelli problem in d-dimensional real normed
spaces or Minkowski spaces, mainly for d=2. Our approach is to study the
Fermat-Torricelli locus in a geometric way. We present many new results, as
well as give an exposition of known results that are scattered in various
sources, with proofs for some of them. Together, these results can be
considered to be a minitheory of the Fermat-Torricelli problem in Minkowski
spaces and especially in Minkowski planes. This demonstrates that substantial
results about locational problems valid for all norms can be found using a
geometric approach.
