Alternative Equation Formats

$$\begin{array}{rcl}{P}_1& =& P_0(S>=s_0)=\underset{x=s_0}{\overset{x=u}{\sum <!--\; \sum \; -->}}{C}_x/\underset{x=l}{\overset{x=u}{\sum <!--\; \sum \; -->}}{C}_x\mathrm{i}\mathrm{f}{s}_0>{\mathrm{E}}_0(S)\\ P_1& =& P_0(S<=s_0)=\underset{x=l}{\overset{x=s_0}{\sum <!--\; \sum \; -->}}{C}_x/\underset{x=l}{\overset{x=u}{\sum <!--\; \sum \; -->}}{C}_x\mathrm{i}\mathrm{f}{s}_0\le <!--\; \le \; -->{\mathrm{E}}_0(S)\end{array}$$

$$\begin{array}{rcl}{P}_1& =& P_0(S>=s_0)=\underset{x=s_0}{\overset{x=u}{\sum <!--\; \sum \; -->}}{C}_x/\underset{x=l}{\overset{x=u}{\sum <!--\; \sum \; -->}}{C}_x\mathrm{i}\mathrm{f}{s}_0>{\mathrm{E}}_0(S)\\ P_1& =& P_0(S<=s_0)=\underset{x=l}{\overset{x=s_0}{\sum <!--\; \sum \; -->}}{C}_x/\underset{x=l}{\overset{x=u}{\sum <!--\; \sum \; -->}}{C}_x\mathrm{i}\mathrm{f}{s}_0\le <!--\; \le \; -->{\mathrm{E}}_0(S)\end{array}$$

\begin{eqnarray*} P_{1} & =& P_0(~ S >= s_0~ ) = \sum _{x~ =~ s_0}^{x~ =~ u} C_ x ~ / ~ \sum _{x~ =~ l}^{x~ =~ u} C_{x} \hspace{.2in} \mr{if} \hspace{.1in} s_0 > \mr{E}_0(S) \\[0.10in] P_{1} & =& P_0(~ S <= s_0~ ) = \sum _{x~ =~ l}^{x~ =~ s_0} C_ x ~ / ~ \sum _{x~ =~ l}^{x~ =~ u} C_{x} \hspace{.2in} \mr{if} \hspace{.1in} s_0 \leq \mr{E}_0(S) \end{eqnarray*}