Your American History Reference Guide!
- Generalized Gauss-Bonnet theorem

HistoryMania Information Site on Generalized Gauss-Bonnet theorem American History American History Search        American History Browse welcome to our free resource site for all enthusiasts!

Generalized Gauss-Bonnet theorem

(Redirected from Chern-Gauss-Bonnet theorem)

In mathematics, the generalized-Gauss-Bonnet theorem presents the Euler characteristic of a closed Riemannian manifold as an integral of a certain polynomial derived from its curvature. It is a direct generalization of the Gauss-Bonnet theorem to general even dimension.

Let M be a compact Riemannian manifold of dimension 2n and Ω be the curvature form of the Levi-Civita connection. This means that Ω is an \mathfrak s\mathfrak o(2n)-valued 2-form on M. So Ω can be regarded as a skew-symmetric 2n × 2n matrix whose entries are 2-forms, so it is a matrix over the commutative ring \bigwedge^{\hbox{even}}T^*M. One may therefore take the Pfaffian of Ω, Pf(Ω) which turns out to be a 2n-form.

The generalized-Gauss-Bonnet theorem states that

Pf(Ω) = 2nπnχ(M)
M

where χ(M) denotes the Euler characteristic of M.

Further generalizations

As with the Gauss-Bonnet theorem, there are generalizations when M is a manifold with boundary.

See also:

  1. Chern-Weil homomorphism,
  2. Pontryagin number,
  3. Pontryagin class.
The contents of this article are licensed from Wikipedia.org under the
GNU Free Documentation License. How to see transparent copy
Search | Browse | Contact | Legal info