THE present French translation from the fourth edition of these lessons on projective geometry by the eminent Italian mathematician-philosopher to a certain extent meets a long-felt want. Perhaps the most striking feature of the book is the remarkably clear and consistent way in which the subject is developed from its logical foundations solely by means of graphical methods, based upon five purely geometrical postulates together with a sixth which is the geometrical equivalent of Dedekind's continuity theorem. Although so much stress is laid upon projective constructions, the relations between projective and metrical geometry are expounded in the text whenever occasion arises, whilst the connexions with group theory and algebraic geometry are touched upon in several appendices.
Leçons de géométrie projective.
Prof. Federigo Enriques. Traduit de la quatrième édition italienne par Prof. P. Labérenne. Pp. iv + 430. (Paris: Gauthier-Villars et Cie, 1930.) 60 francs.