A correspondence between two surfaces such that at corresponding points the radius vector of one of them is parallel to the normal of the other, and vice versa. For every smooth surface in with radius vector there exists (under certain conditions) a surface polar with it and with radius vector , where is the normal and is the support function to , so that
Sometimes these conditions are also included in the definition of a polar correspondence.
The concept of polar correspondence shows itself particularly clearly (in the sense of a complete duality) in centro-affine geometry.
Polar correspondence. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Polar_correspondence&oldid=14085