A simple method for constructing correlative elements in related secunds of points, conoprimas of points and conoprimas of rays with three fixed elements
Abstract
The projective relations elucidated in the preceding note would achieve a high degree of clarity if it were possible to establish, by a simple construction, such a correlation between the conoprimas of a secund and the points of the plane that the extra-elements of the one correspond to the extra-points of the other. In the secund of pencils of rays, there is contained a prima of those which are represented by a pair of points (more precisely, by a pair of linear primas of rays). Since in each linear prima there are three such special conoprimas represented (of which one pair may be imaginary), it is perfectly obvious that the prima of special primas of rays is correlative to a curve of the third order.
None
References
- Reye Geometrie der Lage. I, 250.