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Serie VII, Nr 2

Surface of order three with four real double points (A1).

Mathematical description
The cubic surfaces are given by a homogeneous polynomial of degree 3. If the surface is smooth, it contains 27 lines. In case the surface has isolated singularities (or double points), some of the lines collapse. There is a Coxeter diagram associated with every double point. The singularities can be of type A1, A2, A3, A4, A5, D4, D5 and E6. There are only 20 possible combinations.
This model is representing a singular cubic surface with 4 A1 double points. It has 9 lines on it (complex and real).

Title model and translation
Fläche dritter Ordnung mit 4 reellen C2.
Surface of order three with three real double points (A1).

Text on Sticker and translation
Fl. 3. Ord. mit 4 reellen con. Knpktn.
Surface of order three with 4 real double points.

Dr. Carl Rodenberg
Darmstadt in 1881

L. Brill in Darmstadt

Original price
Mark 12,-

13-15 cm


Schilling, M., Catalog mathematischer Modelle für den höheren mathematischen Unterricht, Leipzig: Verlag von Martin Schilling, 1911