Defining the Θ parts of PμA and DiA in the same way as for QiA, it turns out that PiAχ = PτAχviA +QiAχ + ε2d2DiAχ∕dτ2 is a trivial identity [91Jump To The Next Citation Point]. Note that Pμ Aχ and Di Aχ can be converted into surface integral forms and thus can be evaluated explicitly.