Differential $p$-forms and $q$-vector fields with constant coefficients

Abstract

Differential $p$-forms and $q$-vector fields with constant coefficients are studied. Differential $p$-forms of degrees $p=1,2,n-1,n$ with constant coefficients on a smooth $n$-dimensional manifold $M$ are characterized. In the contravariant case, the obstruction for a $q$-vector field $V_q$ to have constant coefficients is proved to be the Schouten-Nijenhuis bracket of $V_q$ with itself. The $q$-vector fields with constant coefficients of degrees $q=1,2,n-1,n$ are also characterized. The notions of differential $p$-forms and $q$-vector fields with conformal constant coefficients are introduced. For arbitrary degrees $p$ and $q$, such differential $p$-forms and $q$-vector fields are seen to be the solutions to two second-order partial differential systems on $J^2(M,{\mathbb{R}}^n)$, which are reducible to two first-order partial differential systems by adding variables. Computational aspects in solving these systems are discussed and examples and applications are also given.