Example:

To evaluate the vertex in this case, we use the triangular decomposition of :

    

Then we have:

    (12)

In fact we can use the covariance of our ansatz to reduce the general case to this case.

For example, take . Then (2) implies that:

    (13)

More explicitly, this is equal to:

    

Similarly, can be obtained from (12) by the action of the ’th order differential operator as in (13).