Absorbing angles, Steiner minimal trees, and antipodality

Horst Martini, Konrad J. Swanepoel, P. Oloff de Wet

We give a new proof that a star $\{o{p}_i:i=1,...,k\}$ in a normed plane is a Steiner minimal tree of its vertices $\{o,p_1,...,p_k\}$ if and only if all angles formed by the edges a…