A surface of constant Gaussian curvature that can be given parametrically by
(1)
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(2)
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(3)
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where
(4)
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(5)
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(6)
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and ,
and
.
The value of
is restricted to
(7)
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(Reckziegel 1986), and the values correspond to the ends of the cleft in the surface.
The surface illustrated above corresponds to
.
The coefficients of the first fundamental form are given by
(8)
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(9)
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(10)
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with coefficients of the second fundamental form given by similar, but rather complicated, expressions. The Gaussian curvature is
(11)
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with the mean curvature given by a rather complicated expression.