%! TeX program = lualatex
\documentclass{article}

\begin{document}

\begin{equation}
  αβγδϵεζηθϑικλμνξπϖρϱσςτυϕφχψωΓΔΘΛΞΠΣΥΦΧΨΩ
\end{equation}

$\int x \delta x$

$∬ x ∀ y$

$C(x)$

\end{document}
