测试
$$
\begin{align*}
& \phi(x,y) = \phi \left(\sum_{i=1}^n x_ie_i, \sum_{j=1}^n y_je_j \right)
= \sum_{i=1}^n \sum_{j=1}^n x_i y_j \phi(e_i, e_j) = \\
& (x_1, \ldots, x_n) \left( \begin{array}{ccc}
\phi(e_1, e_1) & \cdots & \phi(e_1, e_n) \\
\vdots & \ddots & \vdots \\
\phi(e_n, e_1) & \cdots & \phi(e_n, e_n)
\end{array} \right)
\left( \begin{array}{c}
y_1 \\
\vdots \\
y_n
\end{array} \right)
\end{align*}
$$
System.out.println("");
This is inline \(\sum_{i=1}^n x_ie_i\)
The following is a math block:
\[\sum_{i=1}^n x_ie_i\]But next comes a paragraph with an inline math statement:
\(\sum_{i=1}^n x_ie_i\)
- this is a inline \(\sum_{i=1}^n x_ie_i\)
- this is b inline \(\sum_{i=1}^n x_ie_i\)
- this is c inline \(\sum_{i=1}^n x_ie_i\)
