By H.S.M. Coxeter
In Euclidean geometry, buildings are made with ruler and compass. Projective geometry is less complicated: its structures require just a ruler. In projective geometry one by no means measures something, as a substitute, one relates one set of issues to a different through a projectivity. the 1st chapters of this publication introduce the real techniques of the topic and supply the logical foundations. The 3rd and fourth chapters introduce the recognized theorems of Desargues and Pappus. Chapters five and six utilize projectivities on a line and aircraft, respectively. the following 3 chapters increase a self-contained account of von Staudt's method of the speculation of conics. the fashionable process utilized in that improvement is exploited in bankruptcy 10, which bargains with the easiest finite geometry that's wealthy sufficient to demonstrate the entire theorems nontrivially. The concluding chapters exhibit the connections between projective, Euclidean, and analytic geometry.