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docs/features/Latex.md

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+---
+title: LaTeX
+tags:
+  - feature/transformer
+---
+
+Quartz uses [Katex](https://katex.org/) by default to typeset both inline and block math expressions at build time.
+
+## Syntax
+
+### Block Math
+
+Block math can be rendered by delimiting math expression with `$$`.
+
+```
+$$
+f(x) = \int_{-\infty}^\infty
+    f\hat(\xi),e^{2 \pi i \xi x}
+    \,d\xi
+$$
+```
+
+$$
+f(x) = \int_{-\infty}^\infty
+    f\hat(\xi),e^{2 \pi i \xi x}
+    \,d\xi
+$$
+
+$$
+\begin{aligned}
+a &= b + c \\ &= e + f \\
+\end{aligned}
+$$
+
+$$
+\begin{bmatrix}
+1 & 2 & 3 \\
+a & b & c
+\end{bmatrix}
+$$
+
+$$
+\begin{array}{rll}
+E \psi &= H\psi & \text{Expanding the Hamiltonian Operator} \\
+&= -\frac{\hbar^2}{2m}\frac{\partial^2}{\partial x^2} \psi + \frac{1}{2}m\omega x^2 \psi & \text{Using the ansatz $\psi(x) = e^{-kx^2}f(x)$, hoping to cancel the $x^2$ term} \\
+&= -\frac{\hbar^2}{2m} [4k^2x^2f(x)+2(-2kx)f'(x) + f''(x)]e^{-kx^2} + \frac{1}{2}m\omega x^2 f(x)e^{-kx^2} &\text{Removing the $e^{-kx^2}$ term from both sides} \\
+& \Downarrow \\
+Ef(x) &= -\frac{\hbar^2}{2m} [4k^2x^2f(x)-4kxf'(x) + f''(x)] + \frac{1}{2}m\omega x^2 f(x) & \text{Choosing $k=\frac{im}{2}\sqrt{\frac{\omega}{\hbar}}$ to cancel the $x^2$ term, via $-\frac{\hbar^2}{2m}4k^2=\frac{1}{2}m \omega$} \\
+&= -\frac{\hbar^2}{2m} [-4kxf'(x) + f''(x)] \\
+\end{array}
+$$
+
+> [!warn]
+> Due to limitations in the [underlying parsing library](https://github.com/remarkjs/remark-math), block math in Quartz requires the `$$` delimiters to be on newlines like above.
+
+### Inline Math
+
+Similarly, inline math can be rendered by delimiting math expression with a single `$`. For example, `$e^{i\pi} = -1$` produces $e^{i\pi} = -1$
+
+### Escaping symbols
+
+There will be cases where you may have more than one `$` in a paragraph at once which may accidentally trigger MathJax/Katex.
+
+To get around this, you can escape the dollar sign by doing `\$` instead.
+
+For example:
+
+- Incorrect: `I have $1 and you have $2` produces I have $1 and you have $2
+- Correct: `I have \$1 and you have \$2` produces I have \$1 and you have \$2
+
+### Using mhchem
+
+Add the following import to the top of `quartz/plugins/transformers/latex.ts` (before all the other
+imports):
+
+```ts title="quartz/plugins/transformers/latex.ts"
+import "katex/contrib/mhchem"
+```
+
+## Customization
+
+Latex parsing is a functionality of the [[plugins/Latex|Latex]] plugin. See the plugin page for customization options.