A reduction of the Jacobian Conjecture to the symmetric case

The main result of this paper asserts that it suffices to prove the Jacobian Conjecture for all polynomial maps of the form x + H x+H , where H H is homogeneous (of degree 3) and J H JH is nilpotent and symmetric. Also a 6-dimensional counterexample is given to a dependence problem posed by de Bondt and van den Essen (2003).