> For the complete documentation index, see [llms.txt](https://overleaf-pro.ayaka.space/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://overleaf-pro.ayaka.space/latex/zh-cn/shu-xue/12-mathematical-fonts.md).

# 数学字体

## 引言

某些数学元素需要使用包含某种风格字符/符号的字体进行排版；例如，通常用黑板粗体字体表示实数（例如 $$\mathbb{R}$$），或者用花体字表示拓扑空间（例如（$$\mathcal{T}$$）。本文展示在数学排版中如何使用不同的字体样式，先从下面这个例子开始：

```latex
设 \( \mathcal{T} \) 为一个拓扑空间，基定义为
\[
 \mathcal{B} = \{B_{\alpha} \in \mathcal{T}\, |\,  U = \bigcup B_{\alpha} \forall U \in \mathcal{T} \}
\]
```

[在 Overleaf 中打开此示例](https://www.overleaf.com/docs?engine=pdflatex\&snip_name=Maths+typeface+example\&snip=%5Cdocumentclass%7Barticle%7D%0A%5Cbegin%7Bdocument%7D%0ALet+%5C%28+%5Cmathcal%7BT%7D+%5C%29+be+a+topological+space%2C+a+basis+is+defined+as%0A%5C%5B%0A+%5Cmathcal%7BB%7D+%3D+%5C%7BB_%7B%5Calpha%7D+%5Cin+%5Cmathcal%7BT%7D%5C%2C+%7C%5C%2C++U+%3D+%5Cbigcup+B_%7B%5Calpha%7D+%5Cforall+U+%5Cin+%5Cmathcal%7BT%7D+%5C%7D%0A%5C%5D%0A%5Cend%7Bdocument%7D)

此示例生成以下输出：

![数学字体示例](/files/5f0656a87d1c71a526d4b40069197ab9d7d5f6de)

使用某些数学字体样式需要在 `\usepackage{amssymb}` 行加入文档导言区：参见 [`amsfonts` 宏包](https://ctan.org/pkg/amsfonts) 以获取更多信息。

## 仅支持大写字母的字体类型

有些字体类型只支持有限数量的字符；这些字体通常表示某些特殊集合。例如，要用黑板粗体字体显示 R，可以使用 `\(\mathbb{R}\)` 来生成 $$\mathbb{R}$$。下面的例子展示了花体、Fraktur 体和黑板粗体字体：

```latex
\documentclass{article}
\usepackage{amsmath}
\usepackage{amssymb}
\begin{document}
\begin{align*}
RQSZ \\
\mathcal{RQSZ} \\
\mathfrak{RQSZ} \\
\mathbb{RQSZ}
\end{align*}
\end{document}
```

[在 Overleaf 中打开此示例](https://www.overleaf.com/docs?engine=pdflatex\&snip_name=Using+different+math+fonts\&snip=%5Cdocumentclass%7Barticle%7D%0A%5Cusepackage%7Bamsmath%7D%0A%5Cusepackage%7Bamssymb%7D%0A%5Cbegin%7Bdocument%7D%0A%5Cbegin%7Balign%2A%7D%0ARQSZ+%5C%5C%0A%5Cmathcal%7BRQSZ%7D+%5C%5C%0A%5Cmathfrak%7BRQSZ%7D+%5C%5C%0A%5Cmathbb%7BRQSZ%7D%0A%5Cend%7Balign%2A%7D%0A%5Cend%7Bdocument%7D)

此示例生成以下输出：

![为数学排版更改字体](/files/9f65c6896d88706130d607fe2335d1a4598a5003)

## 其他数学字体

可以为整个数学表达式设置不同的字体族：

```latex
\begin{align*}
3x^2 \in R \subset Q \\
\mathnormal{3x^2 \in R \subset Q} \\
\mathrm{3x^2 \in R \subset Q} \\
\mathit{3x^2 \in R \subset Q} \\
\mathbf{3x^2 \in R \subset Q} \\
\mathsf{3x^2 \in R \subset Q} \\
\mathtt{3x^2 \in R \subset Q}
\end{align*}
```

[在 Overleaf 中打开此示例](https://www.overleaf.com/docs?engine=pdflatex\&snip_name=Using+a+font+family+for+mathematical+expressions\&snip=%5Cdocumentclass%7Barticle%7D%0A%5Cusepackage%7Bamsmath%7D%0A%5Cusepackage%7Bamssymb%7D%0A%5Cbegin%7Bdocument%7D%0A%5Cbegin%7Balign%2A%7D%0A3x%5E2+%5Cin+R+%5Csubset+Q+%5C%5C%0A%5Cmathnormal%7B3x%5E2+%5Cin+R+%5Csubset+Q%7D+%5C%5C%0A%5Cmathrm%7B3x%5E2+%5Cin+R+%5Csubset+Q%7D+%5C%5C%0A%5Cmathit%7B3x%5E2+%5Cin+R+%5Csubset+Q%7D+%5C%5C%0A%5Cmathbf%7B3x%5E2+%5Cin+R+%5Csubset+Q%7D+%5C%5C%0A%5Cmathsf%7B3x%5E2+%5Cin+R+%5Csubset+Q%7D+%5C%5C%0A%5Cmathtt%7B3x%5E2+%5Cin+R+%5Csubset+Q%7D%0A%5Cend%7Balign%2A%7D%0A%5Cend%7Bdocument%7D)

此示例生成以下输出：

![为数学排版更改字体](/files/2fa51b28075ae9144bcd8e7a52610d2a4b94aeda)

在这种情况下，不仅字母，所有字符都会改变外观；例如， `$\mathit{3x^2}$` 将整个表达式斜体化，得到 $$\mathit{3x^2}$$.

## 进一步阅读

更多信息请参见

* [`amsfonts` 包文档](https://ctan.org/pkg/amsfonts)
* [数学表达式](/latex/zh-cn/shu-xue/01-mathematical-expressions.md)
* [下标和上标](/latex/zh-cn/shu-xue/02-subscripts-and-superscripts.md)
* [加粗、斜体和下划线](/latex/zh-cn/latex-ji-chu/03-bold-italics-and-underlining.md)
* [字体大小、字体族和样式](/latex/zh-cn/zi-ti/01-font-sizes-families-and-styles.md)
* [字体字形](/latex/zh-cn/zi-ti/02-font-typefaces.md)
* [文本对齐](/latex/zh-cn/ge-shi-hua/06-text-alignment.md)
* [LaTeX2ε 不那么简短的介绍](http://www.ctan.org/tex-archive/info/lshort/)


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