Testing KaTeX

I really like using LaTeX to write mathematical formulas. Also, I believe that, at some point, it will be convenient to write at least some simple formulae here. After some searches I found exactly what I needed: a KaTeX jekyll plugin. Now I can have beautifully rendered mathematical (and logical) formulae in my posts such as:

\[\forall x \exists y P(x, y) \rightarrow P(y, x).\]