'R markdown (html_pretty) does not show "not equal" symbol properly

I found that "html_pretty" output does not properly show the unequal math symbol.

The following is the minimal reproducible example for it.

---
title: "example"
output:
  prettydoc::html_pretty:
    theme: architect
    highlight: github
    math: katex
---

$$
\mu \neq \mu_0
$$

This shows

However, the regular "html_document" format works, showing $\noteq$ as we want.

---
title: "Untitled"
output: html_document
---

$$
\mu \neq \mu_0
$$

Do you have any idea about the reason? How do I use the unequal symbol in "html_pretty" format?

html r-markdown

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Solution	Source