Math Mode Greek Letters – Setting Uppercase Greek Letters as Italic by Default

greekitalicmath-modesymbols

This is a follow up question to here.

The recommended solution doesn't work for me. I therefore let all my mathematical packages in the MWE. The result is an upright Psi followed by an italic Psi. I would like to have all upper-case Greeks being italic in formulas. The possibility to set one character upright (for a constant, an operator…) would be great. Therefore I wonder, if there is a more beautiful solution around.

\documentclass[]{scrreprt}

\usepackage[final]{microtype}
\usepackage{luatextra}
\usepackage{fontenc}
    \defaultfontfeatures{Ligatures={TeX}}
\usepackage[ngerman, english]{babel}
\useshorthands{"}
\addto\extrasenglish{\languageshorthands{ngerman}}
\usepackage{amsmath}
\let\Gamma\varGamma
\let\Delta\varDelta
\let\Theta\varTheta
\let\Lambda\varLambda
\let\Xi\varXi
\let\Pi\varPi
\let\Sigma\varSigma
\let\Upsilon\varUpsilon
\let\Phi\varPhi
\let\Psi\varPsi
\let\Omega\varOmega
\usepackage{mathtools}
\usepackage{amssymb}
\usepackage{commath}
\usepackage[
per-mode=symbol-or-fraction,
locale=DE,
sticky-per
]{siunitx} 
\usepackage{xfrac}
%
\begin{document}
$\Psi \varPsi$
\end{document}

Edit My knowledge over the used math-packages is quite small. Don't know, if I use them at all (amssymb and mathtools). If they are obsolete or not recommended for typesetting in Germany (English and German) or if something is missing for typical formula setting, I would be glad for every advise.

Best Answer

My advice is to use unicode-math:

\documentclass{scrreprt}
\usepackage[ngerman, english]{babel}

\usepackage{amsmath}
\usepackage[math-style=ISO]{unicode-math}
\usepackage[final]{microtype}

\usepackage[table]{xcolor}
\usepackage[
  per-mode=symbol-or-fraction,
  locale=DE,
  sticky-per
]{siunitx}

\useshorthands{"}
\addto\extrasenglish{\languageshorthands{ngerman}}

\begin{document}
$\Psi \symup{\Psi}$
\end{document}

enter image description here

You can see that the default is slanted, but with \symup you can get the upright letter.

With unicode-math you don't need amssymb. Load mathtools, if you want it, in place of amsmath before unicode-math.

Don't load commath: it is buggy.

Note: in the previous version of the code \mathup was used, but unicode-math underwent some changes and now \symup is the command to use for this purpose.

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