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Serie VII, Nr 11

Surface of order three with an A2 double point, whose tangent planes at that point are imaginary conjugated.


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 cubic surface has one A2 double point and 15 lines. Its tangent planes at that point are imaginary conjugated.

Title model and translation
Fläche dritter Ordnung mit B3, dessen Ebenen conjugiert imaginär sind.
Surface of order three with an A2 double point, whose tangent planes at that point are imaginary conjugated.

Text on Sticker and translation
Fl. 3. Ord. mit bipl. Knotenpunkt B3.
Surface of order three with an A2 double point.

Designer
Dr. Carl Rodenberg
Darmstadt in 1881

Company
L. Brill in Darmstadt

Original price
Mark 10,-

Dimension
12-15 cm

Material
Plaster

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