ABSTRACT
In physics, we often consider a differential operator defined on a manifold M. Typical examples will be the Laplacian, the d’Alembertian and the Dirac operator. From the mathematical point of view, these operators are regarded as maps of sections D : Γ ( M , E ) → Γ ( M , F ) https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315275826/f89ac38d-581c-4b20-9248-de0a1dc00421/content/eq3796.tif"/>
