Kuen surface
The Kuen surface is a mathematical surface of constant negative unit Gaussian curvature, making it an example of a pseudospherical surface. It can be described as a parametric surface in terms of the parametric equations x = 2 cosh v ( cos u + u sin u ) / w {\displaystyle x=2\cosh v\,(\cos u+u\sin u)/w} y = 2 cosh v ( sin u − u cos u ) / w {\displaystyle y=2\cosh v\,(\sin u-u\cos u)/w} z = v − ( 2 sinh v cosh v ) / w {\displaystyle z=v-(2\sinh v\cosh v)/w} where w = ( cosh v ) 2 + u 2 {\displaystyle w=(\cosh v)^{2}+u^{2}} It is named after, and was first described by, the German mathematician Theodor Kuen in 1884.