Please refrain from using TeX/MathJax in Titles!
This is more on how not to use MathJax, but still good to keep in mind.
A good overview of why not to do this is here, but let me briefly summarize:
- Titles are used in places that do not render TeX!
- If you must describe your title with TeX, you probably aren't summarizing your question enough. Try to make a natural language title, that is usually possible and summarizes your question better.