markdown

\mathcal{Pro}

$\mathcal{P}ro$

\mathbb{Pro}

$\mathbb{P}ro$

\mathrm{Pro}

$\mathrm{P}\mathrm{r}\mathrm{o}$

\dbinom{} {} \large{\sum \limits _{k = 0} ^{n}}

$\left(\genfrac{}{}{0ex}{}{}{}\right)\sum _{k=0}^n$

\begin{aligned} &a \\ b&b \end{aligned}

$\begin{array}{rl}& a\\ b& b\end{array}$

\begin{cases} a = 1 \\ b = 0 \end{cases}

$\{\begin{array}{l}a=1\\ b=0\end{array}$