We prove that under some conditions every nonparametric capillary
surface which has a central fan (of radial limits at a point
)
can be perturbed with respect to the contact angle and the perturbed
surfaces continue to have central fans. In particular, any nonparametric
capillary surface which is symmetric with respect to a vertical plane through
and has a central fan may be perturbed (with respect to the contact angle)
in a nonsymmetric manner and the resulting capillary surfaces will not be
symmetric with respect to the vertical plane but will continue to have central
fans.
Keywords
capillary surfaces, nonconvex corner, central fans