Why is nomath option not working with stix2?

Question

This might just be me not knowing how to usepackage but \usepackage[nomath]{stix2} is (I think) not letting the package work, eg mathbb isn't defined, and \usepackage[nomath=true]{stix2} says undefined option. Am I misunderstanding the "Do not change the default math fonts" option? I just want the capital psi to look the same as in usual math mode, and not the stix version.

Answer 1

stix2 options do not take values [nomath=true] is incorrect.

[nomath] prevents the package loading math fonts, so you get the standard math fonts, so \mathbb is undefined unless you load some package such as amsfonts that defines it.

You can of course load the original cm font and access its Greek if you wish but I wouldn't advise it, stix and computer modern are not intended to be visually compatible.

\documentclass{article}
\usepackage{stix2}
\DeclareSymbolFont{cmoperators}   {OT1}{cmr} {m}{n}
\DeclareMathSymbol{\cmGamma}{\mathalpha}{cmoperators}{"00}
\DeclareMathSymbol{\cmDelta}{\mathalpha}{cmoperators}{"01}
\DeclareMathSymbol{\cmTheta}{\mathalpha}{cmoperators}{"02}
\DeclareMathSymbol{\cmLambda}{\mathalpha}{cmoperators}{"03}
\DeclareMathSymbol{\cmXi}{\mathalpha}{cmoperators}{"04}
\DeclareMathSymbol{\cmPi}{\mathalpha}{cmoperators}{"05}
\DeclareMathSymbol{\cmSigma}{\mathalpha}{cmoperators}{"06}
\DeclareMathSymbol{\cmUpsilon}{\mathalpha}{cmoperators}{"07}
\DeclareMathSymbol{\cmPhi}{\mathalpha}{cmoperators}{"08}
\DeclareMathSymbol{\cmPsi}{\mathalpha}{cmoperators}{"09}
\DeclareMathSymbol{\cmOmega}{\mathalpha}{cmoperators}{"0A}
\begin{document}
$ \Phi + \cmPhi + \emptyset + \varnothing + \Psi + \cmPsi $
\end{document}