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PINCH POINT

Other names: cuspidal point, Whitney singular point.
See also: www.jp-petit.org/Extensions/bcuspi/bcuspi.htm |

End of a self-intersection line of the surface. At such a point, a tangent plane cannot be defined.

See examples in Whitney's umbrella, the cross-cap, the Roman surface, and the sine surface.

See also conical points.

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© Robert FERRÉOL 2017