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Kuen Surface


KuenSurface

The Kuen surface is a special case of Enneper's negative curvature surfaces which can be given parametrically by

x=(2(cosu+usinu)sinv)/(1+u^2sin^2v)
(1)
=(2sqrt(1+u^2)cos(u-tan^(-1)u)sinv)/(1+u^2sin^2v)
(2)
y=(2(sinu-ucosu)sinv)/(1+u^2sin^2v)
(3)
=(2sqrt(1+u^2)sin(u-tan^(-1)u)sinv)/(1+u^2sin^2v)
(4)
z=ln[tan(1/2v)]+(2cosv)/(1+u^2sin^2v)
(5)

for v in [0,pi), u in [0,2pi) (Reckziegel et al. 1986; Gray et al. 2006, p. 484).

The Kuen surface appears on the cover of volume 2, number 1 of La Gaceta de la Real Sociedad Matemática Española (1999).

The coefficients of the first fundamental form are

E=(16u^2sin^2v)/([2+u^2-u^2cos^2(2v)]^2)
(6)
F=0
(7)
G=csc^2v-(16u^2sin^2v)/([2+u^2-u^2cos^2(2v)]^2),
(8)

the second fundamental form coefficients are

e=-(4u[2-u^2+u^2cos^2(2v)]sinv)/([2+u^2-u^2cos^2(2v)]^2)
(9)
f=0
(10)
g=(4u[2-u^2+u^2cos^2(2v)]cscv)/([2+u^2-u^2cos^2(2v)]^2),
(11)

and the surface area element is

 dS=(4u[2-u^2+u^2cos(2v)])/([2+u^2-u^2cos^2(2v)]^2).
(12)

The Gaussian and mean curvatures are

K=-1
(13)
H=-(cscv)/(4u)+1/4usinv[1+8/(2-u^2+u^2cos(2v))],
(14)

so the Kuen surface has constant negative Gaussian curvature, and the principal curvatures are

kappa_1=(4usinv)/(2-u^2+u^2cos(2v))
(15)
kappa_2=-([2-u^2+u^2cos(2v)]cscv)/(4u)
(16)

(Gray 1997, p. 496).


See also

Enneper's Negative Curvature Surfaces

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References

Cover of La Gaceta de la Real Sociedad Matemática Española 2, 1999.Fischer, G. (Ed.). Plate 86 in Mathematische Modelle aus den Sammlungen von Universitäten und Museen, Bildband. Braunschweig, Germany: Vieweg, p. 82, 1986.Gray, A.; Abbena, E.; and Salamon, S. "Kuen's Surface as Bianchi Transform of the Pseudosphere." §21.7 In Modern Differential Geometry of Curves and Surfaces with Mathematica, 3rd ed. Boca Raton, FL: CRC Press, pp. 484 and 704-706, 2006.JavaView. "Classic Surfaces from Differential Geometry: Kuen." http://www-sfb288.math.tu-berlin.de/vgp/javaview/demo/surface/common/PaSurface_Kuen.html.Kuen, T. "Ueber Flächen von constantem Krümmungsmass." Sitzungsber. d. königl. Bayer. Akad. Wiss. Math.-phys. Classe, Heft II, 193-206, 1884.Nordstrand, T. "Kuen's Surface." http://jalape.no/math/kuentxt.Reckziegel, H. "Kuen's Surface." §3.4.4.2 in Mathematical Models from the Collections of Universities and Museums (Ed. G. Fischer). Braunschweig, Germany: Vieweg, p. 38, 1986.

Cite this as:

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

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