On some types of vector fields on manifolds with Levi-Civita structure

In this note one studies some types of vector fields on a Riemmannian manifold $M$ endowed with a Levi-Civita connection $\nabla$. For instance some types of closed torse forming, exterior concurrent vector fields, and quasi exterior concurrent vector fields. In addition exterior concurrents valued 1-form are also discussed. Finally we state and prove the following proposition: Let X and X' be exterior concurrent vector fields with respective conformal scalar f and f'. Then F = X \land X' is a 2-exterior concurrent vector valued 1-form having $(f+f') (x^b \land x^b')$ as concurrence form