 Instead it defines a more general structure introduced by [[Zhang-Ju Liu]], [[Alan Weinstein]] and [[Ping Xu]] known as a [[Courant algebroid]].The Courant bracket may be twisted by a "(p+2)"-form "H", by adding the interior product of the vector fields "X" and "Y" of "H".It remains antisymmetric and invariant under the addition of the interior product with a "(p+1)"-form "B".