Mappings preserving regular hexahedrons.
Mappings which preserve regular dodecahedrons.
Mehrdimensionales Analogon zu den Sätzen von Menelaos und Ceva
Metric characterizations of hyperbolic and Euclidean spaces
Metric rigidity of crystallographic groups.
Mini-programs for hidden lines on a surface
Many programs for the hidden lines on a surface are known [1] but these programs are long and need a large memory of the computer. In this paper we show algorithms and the corresponding mini-program in BASIC which can be implemented on minicomputers with plotters or plotting displays. We map the surface in the parallel or central projections.