Spherical aggregates of conoprimas
Abstract
One of the very first principles of the new geometry is the theorem according to which projectivity on lines (linear and quadratic) is established by the correspondence of three elements. Therefore, if four arbitrary lines are given on a plane, then each of them, at its intersection with the other three, gives three points, and this is sufficient to establish the projectivity of points on all these lines, because on each of them we have three corresponding points. If spherical aggregates are given partly by real, partly by imaginary conoprimas, then from them it is necessary to construct two linear aggregates of the same degree, for one of which the value of the class of conoprimas must be changed: the real taken as imaginary and vice versa.
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