This textbook is suitable for a one semester lecture course on
differential geometry for students of mathematics or STEM disciplines
with a working knowledge of analysis, linear algebra, complex analysis,
and point set topology. The book treats the subject both from an
extrinsic and an intrinsic view point.
The first chapters give a historical overview of the field and contain
an introduction to basic concepts such as manifolds and smooth maps,
vector fields and flows, and Lie groups, leading up to the theorem of
Frobenius. Subsequent chapters deal with the Levi-Civita connection,
geodesics, the Riemann curvature tensor, a proof of the
Cartan-Ambrose-Hicks theorem, as well as applications to flat spaces,
symmetric spaces, and constant curvature manifolds. Also included are
sections about manifolds with nonpositive sectional curvature, the Ricci
tensor, the scalar curvature, and the Weyl tensor.
An additional chapter goes beyond the scope of a one semester lecture
course and deals with subjects such as conjugate points and the Morse
index, the injectivity radius, the group of isometries and the
Myers-Steenrod theorem, and Donaldson's differential geometric approach
to Lie algebra theory.