The question of existence of c10sed geodesics on a Riemannian manifold and the properties of the corresponding periodic orbits in the geodesic flow has been the object of intensive investigations since the beginning of global differential geo- metry during the last century. The simplest case occurs for c10sed surfaces of negative curvature. Here, the fundamental group is very large and, as shown by Hadamard [Had] in 1898, every non-null homotopic c10sed curve can be deformed into a c10sed curve having minimallength in its free homotopy c1ass. This minimal curve is, up to the parameterization,...

Das vorliegende Buch ist aus einer 1-semestrigen Vorlesung iiber DifTerentialgeometrie entstanden, die ich wiederholt in Gottingen, Mainz und Bonn gehalten habe. Mit dieser Vorlesung verfolgte ich das Ziel, den Studenten mittlerer Semester, die die Anfangervorlesungen gemeistert haben, eine Einfiihrung in die klassische Differentialgeometrie der Kurven und FIachen anzubieten und damit eine Alternative zu offerieren zu anderen Vorlesungen fiir mittlere Semester, wie etwa Funktionen theorie, Hohere Algebra oder Algebraische Topologie. Fiir den groBten Teil der Vorlesung wird nichts weiter als...

The question of existence of c10sed geodesics on a Riemannian manifold and the properties of the corresponding periodic orbits in the geodesic flow has been the object of intensive investigations since the beginning of global differential geo- metry during the last century. The simplest case occurs for c10sed surfaces of negative curvature. Here, the fundamental group is very large and, as shown by Hadamard [Had] in 1898, every non-null homotopic c10sed curve can be deformed into a c10sed curve having minimallength in its free homotopy c1ass. This minimal curve is, up to the parameterization,...

This English edition could serve as a text for a first year graduate course on differential geometry, as did for a long time the Chicago Notes of Chern mentioned in the Preface to the German Edition. Suitable references for ordin- ary differential equations are Hurewicz, W. Lectures on ordinary differential equations. MIT Press, Cambridge, Mass., 1958, and for the topology of surfaces: Massey, Algebraic Topology, Springer-Verlag, New York, 1977. Upon David Hoffman fell the difficult task of transforming the tightly constructed German text into one which would mesh well with the more relaxed...