Veblen, Oswald, 1880-1960, Young, John Wesley, 1879-1932 · Boston, New York [etc.] Ginn and Company · leaf 132
and let Pbe a variable point of this conic. Let pv p2, ps, p be respectively thetangents at these points (fig. 57). By the corollary of Theorem 28,Chap. IV, P^ is the axis of homology of the projectivity between thepencils of points on p1 and p2 defined by I>l(PlP2)(P1PS) -X (P*Pl)MP*Pj- But by… … Fig. 57 point pxp is p2p; i.e. p is the line joining pairs of homologous pointson the two lines pv p2, so that the totality of the lines p satisfies thedefinition of a line conic. Corollary. The center of homology of the projectivity Px [P] -^ P2 [P]determined oy the points P of a point conic…
Geometry, Projective
Internet Archive · Wellesley College Library · Public Domain Mark 1.0. Free to use for anything.
