摘要：All perspective collineations in a real affine plane are classified according to a constant cross-ratio and the position of the center and axis. A special attention will be given to the conditions which basic elements of perspective collineation have to fulfill in order to obtain the touch or osculation or hyperosculation of two conics. On the affine models of an isotropic and pseudo-Euclidean plane the osculating circle of a conic is constructed by using perspective collineations.
关键词：perspective collineation; homology; elation; constant cross-ratio; conic; osculating circle
