Bold math symbols as in text mode. Old Standard TT XeLaTeX fontsetup

Question

I am using XeLaTeX 2023 compiler with an Old Standard TT font for both text and math modes. However, bold font in math mode doesn't work at all.

I want to use as the default bold math symbols the appropriate bold text symbols of the font: alphabetical symbols (Latin and Greek) as in in italics+bold, and number digits as in the regular text. I do also wish they all will be auto-scalable.

The first line shows text mode italics and regular characters and the same looking characters are present in math mode below.

The third line shows text mode bold italics and simply bold characters. These should be present in math mode below, but they are not.

Please note the difference between signs for +, -, <, >, etc. in text mode and math modes. Hence, we should not use bold text operation, relation, etc. symbols as bold math font directly.

Any solution of the problem will please my needs. Thank you all so much in advance!

Minimal working example:

\documentclass[leqno,12pt]{extarticle}
\usepackage[paperheight=169mm,paperwidth=120mm,top=12pt,left=12pt,right=12pt,bottom=44pt]{geometry}
\usepackage{parskip}
\usepackage[oldstandard]{fontsetup}

\begin{document}

\textit{y A} 0 1 2 \textit{α β γ δ ε θ λ μ ξ π ρ τ φ χ ψ ω + -- < > = , . : ;}\\
$y, A, 0, 1, 2, \alpha, \beta, \gamma, \delta, \varepsilon, \theta, \lambda, \mu, \xi, \pi, \rho, \tau, \varphi, \chi, \omega, +, -, <, >, =, ., :, ;$

\textbf{\textit{y A} 0 1 2 \textit{α β γ δ ε θ λ μ ξ π ρ ς τ φ χ ψ ω + -- < > = , . : ;}}\\
\boldmath{$y, A, 0, 1, 2, \alpha, \beta, \gamma, \delta, \varepsilon, \theta, \lambda, \mu, \xi, \pi, \rho, \sigma, \tau, \varphi, \chi, \omega, +, -, <, >, =, ., :, ;$}

\end{document}

Answer 1

This is because unicode-math does not support the range and version options of \setmathfont at the same time. You can either set up \setmathfont[version=bold] or use Old Standard letters in math mode, but not both. The package you used does the latter.

If you just want bold letters, for vectors and such, you can use \symbfup for bold upright and \symbfit for bold italic. The \mathbf command should give you symbols from the bold text font in math mode, if Old Standard Bold has them. These won’t have correct spacing unless you specify the class, such as \mathbin, \mathrel, etc. For instance, \mathbin{\mathbf{+}}.

If you need a specific bold math symbol that’s not in Old Standard, you might access it through a \setmathfontface. However, fontsetup uses Garamond Math for its math symbols, which doesn’t come in bold. You can either use the FakeBold option, or take it from XITS Math Bold instead.

If you really, truly need to switch to a bold math environment, consider defining one that changes \setmathfont and then restores it. Alternatively, choose a math font that matches the text font without the need for \setmathfont[range=.