Let E→M be a vector bundle over the manifold M, and ∇ is a connection. I define a differential d for the exterior forms with values in the endomorphisms of E:
d(A)(X)=[∇X,A]
d(AZ)(X,Y)=[∇X,AY]−[∇Y,AX]−A[X,Y]
and for the other degrees, I define d by the Leibniz rule:
d(α∧β)=d(α)∧β+(−1)deg(α)α∧d(β)
Can we have d2=0, and can we define a cohomology?