Manfred Evers, Generalizing orthocorrespondence,
Forum Geometricorum, 12 (2012) 255--281.

Abstract.   B. Gibert [Forum Geom., 3 (2003) 21--27] investigates a transformation  P
→ P of the plane of a triangle ABC, which he calls orthocorrespondence. Important for the definition of this transformation is the tripolar line of P with respect to ABC. This line can be interpreted as a polar-euclidean equivalent of the orthocenter H of the triangle ABC, the point P getting the role of the absolute pole of the polar-euclidean plane. We propose to substitute the center H by other triangle centers and will investigate the properties of such correspondences.

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