--- trunk/tengDissertation/Introduction.tex 2006/05/25 21:32:14 2776 +++ trunk/tengDissertation/Introduction.tex 2006/05/26 17:56:36 2778 @@ -846,12 +846,12 @@ can obtain \] Applying Baker-Campbell-Hausdorff formula to Sprang splitting, we can obtain -\begin{equation} -\exp (h X/2)\exp (h Y)\exp (h X/2) & = & \exp (h X + h Y + h^2 -[X,Y]/4 + h^2 [Y,X]/4 \\ & & \mbox{} + h^2 [X,X]/8 + h^2 [Y,Y]/8 \\ -& & \mbox{} + h^3 [Y,[Y,X]]/12 - h^3 [X,[X,Y]]/24 & & \mbox{} + -\ldots ) -\end{equation} +\begin{eqnarray} +\exp (h X/2)\exp (h Y)\exp (h X/2) & = & \exp (h X + h Y + h^2 [X,Y]/4 + h^2 [Y,X]/4 \\ + & & \mbox{} + h^2 [X,X]/8 + h^2 [Y,Y]/8 \\ + & & \mbox{} + h^3 [Y,[Y,X]]/12 - h^3[X,[X,Y]]/24\\ + & & \mbox{} + \ldots ) +\end{eqnarrary} Since \[ [X,Y] + [Y,X] = 0\] and \[ [X,X] = 0\], the dominant local error of Spring splitting is proportional to $h^3$. The same procedure can be applied to general splitting, of the form