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# Togliatti Surface

Togliatti (1940, 1949) showed that quintic surfaces having 31 ordinary double points exist, although he did not explicitly derive equations for such surfaces. Beauville (1978) subsequently proved that 31 double points are the maximum possible, and quintic surfaces having 31 ordinary double points are therefore sometimes called Togliatti surfaces. van Straten (1993) subsequently constructed a three-dimensional family of solutions and in 1994, Barth derived the example

where is a parameter (Endraß 2003), illustrated above for .

This surface is invariant under the group and contains exactly 15 lines. Five of these are the intersection of the surface with a -invariant cone containing 16 nodes, five are the intersection of the surface with a -invariant plane containing 10 nodes, and the last five are the intersection of the surface with a second -invariant plane containing no nodes (Endraß 2003).

Dervish, Ordinary Double Point, Quintic Surface

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## References

Beauville, A. "Surfaces algébriques complexes." Astérisque 54, 1-172, 1978.Endraß, S. "Togliatti Surfaces." Feb. 6, 2003. http://enriques.mathematik.uni-mainz.de/docs/Etogliatti.shtml.Hunt, B. "Algebraic Surfaces." http://www.mathematik.uni-kl.de/~hunt/drawings.html.Togliatti, E. G. "Una notevole superficie de ordine con soli punti doppi isolati." Vierteljschr. Naturforsch. Ges. Zürich 85, 127-132, 1940.Togliatti, E. "Sulle superficie monoidi col massimo numero di punti doppi." Ann. Mat. Pura Appl. 30, 201-209, 1949.van Straten, D. "A Quintic Hypersurface in with 130 Nodes." Topology 32, 857-864, 1993.

## Cite this as:

Weisstein, Eric W. "Togliatti Surface." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/TogliattiSurface.html