Note then that D p ∆ contains dp (0) which we denote for the ease of notation with dp 1 dp 2 dp 3 . Further, D x ∆ contains dx (0) . And this is denoted for ease of notation by dy 1 dy 2 dy 3 . In effect we have now the S of ( ). Let's write q t,s x,y (θ) = q(θ) and qt,s