Topics In Theory Of Surfaces In Elliptic Space | A. V. Pogorelov

This book deals with the solution of a number ofproblems in the theory of surfaces in elliptic space,through consideration of isometric surfaces. Theprincipal method of investigation is comparison of apair of isometric figures in elliptic space with a pairof isometric figures in a Euclidean space which cor-responds geodesically to the elliptic space. This enables us to transpose the main difficulties in the proof to Euclidean space, where they can be over- come by the appropriate theorems.