--- trunk/tengDissertation/Introduction.tex 2006/05/26 17:56:36 2778 +++ trunk/tengDissertation/Introduction.tex 2006/05/26 18:25:41 2779 @@ -846,12 +846,11 @@ can obtain \] Applying Baker-Campbell-Hausdorff formula to Sprang splitting, we can obtain -\begin{eqnarray} +\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} + & & \mbox{} + h^3 [Y,[Y,X]]/12 - h^3[X,[X,Y]]/24 + \ldots ) +\end{eqnarray*} 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 @@ -859,7 +858,7 @@ Careful choice of coefficient $a_1 ,\ldot , b_m$ will \varphi _{b_m h}^2 \circ \varphi _{a_m h}^1 \circ \varphi _{b_{m - 1} h}^2 \circ \ldots \circ \varphi _{a_1 h}^1 . \end{equation} -Careful choice of coefficient $a_1 ,\ldot , b_m$ will lead to higher +Careful choice of coefficient $a_1 \ldot b_m$ will lead to higher order method. Yoshida proposed an elegant way to compose higher order methods based on symmetric splitting. Given a symmetric second order base method $ \varphi _h^{(2)} $, a fourth-order symmetric