Sans-Serif lower case Greek for mathpazo

Question

Question: Is it possible to get bold sans serif lowercase greek when the document is using mathpazo?

I have a problem with Sans Serif fonts in math environment when using mathpazo package. The following MWE produces expected results for sans serif lower case greek \sigma , without mathpazo.

\documentclass[12pt,a4paper]{article}
\usepackage{amsmath,amssymb}
\usepackage{amsfonts}
% \usepackage{mathpazo}
\usepackage[eulergreek]{sansmath}
\usepackage{bm}
\begin{document}
    $\bm \varepsilon$ \quad
    $\bm \sigma$ \quad
    $\sansmath{\bm \sigma}$
\end{document}

The result of above MWE is:

However, when using mathpazo

\documentclass[12pt,a4paper]{article}
\usepackage{amsmath,amssymb}
\usepackage{amsfonts}
% \usepackage{mathpazo}
\usepackage[eulergreek]{sansmath}
\usepackage{bm}
\begin{document}
    $\bm \varepsilon$ \quad
    $\bm \sigma$ \quad
    $\sansmath{\bm \sigma}$
\end{document}

The result is no Sans Serif for lower case greek:

I am using sansmath package because the mathpazo Palatino package is missing sans-serif fonts (as mentioned here).

Furthermore as mentioned in documentation here, when using sansmath, since the OT1 text fonts do not provide the lower-case greek letters, one has to use package option [eulergreek] to take the lowercase greek from the Euler maths fonts. But even then it does not work.

I have been searching internet for more than a week, but couldn't find the solution.

The template for thesis uses mathpazo/Palatino, therefore I have to follow it, but additionally I need some sans serif lower case greek $\sigma$ and $\varepsilon$.

Answer 1

You can redefine the greek commands (I use \ssigma here for the comparision).

\documentclass[12pt,a4paper]{article}
\usepackage{amsmath,amssymb}
\usepackage{amsfonts}
\usepackage{mathpazo}


\DeclareSymbolFont{EulerGreek}{U}{eur}{m}{n}
\SetSymbolFont{EulerGreek}{normal}{U}{eur}{m}{n}

\SetSymbolFont{EulerGreek}{bold}{U}{eur}{b}{n}

\DeclareMathSymbol{\ssigma}{\mathord}{EulerGreek}{"1B}
\DeclareMathSymbol{\svarepsilon}{\mathord}{EulerGreek}{"22}
\usepackage{bm}
\begin{document}
    $\varepsilon \svarepsilon \bm \varepsilon \bm\svarepsilon $ \quad
    $\sigma \ssigma \bm \sigma \bm\ssigma$ 
\end{document}

A list for the glyph slots is here: https://tex.stackexchange.com/a/335857/2388.