Cognate geometric systems

Abstract

When dualism was recognized in the New Geometry, only two geometric systems were assumed: a system of points and a correlative system of planes. This note aims to show the special significance of such a particular case, which is expressed by the following theorem, if we call two such correlative systems, in which the spheroprims of one are correlative to the spheroprims of the other, cognate systems. All constructions, and therefore theorems, of one related system are transferred to another. In addition, I mean to show that it is possible to establish such systems that for each of its linear seconds it is possible to reproduce a related system of points on the plane.