$$$J_\alpha(x) = \sum\limits_{m=0}^\infty \frac{(-1)^m}{m! \, \Gamma(m + \alpha + 1)}{\left({\frac{x}{2}}\right)}^{2 m + \alpha}$$$
##上下标
- - -
$$$x^{2},
x^{(n)}_{2},
^{-16}O_{32}^{2-},
x^{y^{z^{a}}},
x^{y_{z}},
\partial f_{\tiny hfd};
y_N, y_{_N},y_{_{\scriptstyle N}}
$$$
##分数
- - -
$$$
\frac{a}{b},
a/b,
\frac{x+y}{y+z},
\displaystyle\frac{x+y}{x+z},
x_0 + \frac{1}{x_1+\frac{1}{x_2+\frac{1}{x_4}}},
\frac{1}{2},
\frac{\;1\;}{\;2\;}
$$$
$$\frac{x+y}{y+z}$$
##根号
- - -
$$
\sqrt 2,
\sqrt{x},
\sqrt[n]{x},
\sqrt{a}+\sqrt{b}+\sqrt{c},
\sqrt{\mathstrut a}+\sqrt{\mathstrut b},
\begin{eqnarray}
\sqrt{1+\sqrt[p]{1+\sqrt[q]{1+a}}}\\
\sqrt{1+\sqrt[^p\!]{1+\sqrt[^q\!]{1+a}}}
\end{eqnarray},
^n\!a,
\surd{\frac{x+y+z}{abc}}
$$
##求和
$$$
\sum_{k=1}^n,
\int_a^b,
\sum_{k=1}^\infty \frac{x^n}{n!},
\
$$$
$$
\sum_{k=1}^\infty \frac{x^n}{n!},
\sum_{\infty}^{k=1}\frac{x^n}{n!},
\int_0^\infty e^x,
\sum_{k=1}^\infty = \int_0^\infty e^x,
\sum\limits_{k=1}^{\infty},
\sum\nolimits_{k=1}^{\infty},
$$
##下划线
$$$
\overline{a-b},
\underline{a+b},
\overbrace{a+b}^{上括弧},
\underbrace{a-b}_{下括弧},
\dots
$$$
$$$
\hat{a},
\check{a},
\breve{a},
\tilde{a},
\bar{a},
\vec{a},
\acute{a},
\grave{a},
\mathring{a},
\dot{a},
\ddot{a},
\widehat{a,b,c},
\widetilde{xyz}
$$$
##堆积符号
$$$
\begin{eqnarray*}
\vec{x}\stackrel{\mathrm{def}}{=}{x_1, \dots, x_n}\\
{n+1 \choose k}={n \choose k} + {n \choose k-1}\\
\sum_{k_0,k_1,\ldots>0 \atop k_0+k_1+\cdots=n}A_{k_0}A_{k_1}\cdots
\end{eqnarray*},
\;\;\;\;
\vec{1},
\stackrel{\mathrm{def}}{=}{x_1, \dots, x_n},
{n+1 \choose k} = {n \choose k}+{n \choose k-1},
\sum\limits_{k_0, k_1,\ldots>0 \atop k_0 +k_1 + \cdots = n}A_{k_0}A_{k_1}
$$$
$${n \choose k}, \ldots$$
##定界符
$$$
()
\big(\big)
\Big(\Big)
\bigg(\bigg)
\Bigg(\Bigg)
$$$
