Let f: \R^n -> \R^n be a function. What would you call the function g: x -> x' f(x) ? Furthermore, if F:\R^n -> \R^n is a linear operator and D \in \R^{n X m} a matrix, how would you refer to the operator G: D -> D' F (D) ? Does this appear in a particular physics or engineering context? Note, I use dash ' to mean transpose.