Notes on the format of writing papers in Latex

Note the format for writing papers in Latex:

1. Collection format: $\mathcal{D}$:$\mathcal{D}$

2. Vector bold: $\mathbf{X^{(b)}}$:$\mathbf{X^{(b)}}$
Bold references to packages:\usepackage{bm} %加粗

3. Collection of hollow letters: $\mathbb{R}$:$\mathbb{R}$
Quoting a package: \usepackage{amsfonts,amssymb}% open letter

4. Single quote orientation issue:$`$
The ~ key above the Tab key, is an opening quotation mark$`$;
if double quotes are required, use twice$``$。

5.