Use libertine math font just for the complexity package

Question

I'm currrently using the complexity package, where I have defined a lot of new commands for complexity classes, and I'm writing my document using the libertine font. I want to use the regular math font for everything except for the commands rendered by the complexity package... That is, I want the commands defined by the complexity package to use the math font libertinust1math while the rest of the math should be rendered in the usual math font.

I imagine there must be a simple command to change the font of specific commands, but I don't know that it is.

Are you using LuaLaTeX? You could probably use \fontspec and \newfontfamily. — Ingmar, Jun 05 '22 at 11:44
For the rest sentence, I don't think there's one. You might have to resort to learning TeX programming and copy paste the appropriate lines from the font file, depends on the cases (for XeLaTeX/LuaLaTeX it's a bit easier with fontspec — user202729, Jun 05 '22 at 12:49
@egreg What would be the right math font for Libertine? I've seen libertinust1math but it is rather ugly, so I tried newtxmath instead, which is the combination the ACM proceedings use, I believe. Is there a better combination you suggest? — Noel Arteche, Jun 05 '22 at 15:33

score 1 · Answer 1 · answered Jun 05 '22 at 12:58

The following does what was requested in the question (tested with pdflatex). I leave it up to the author to choose matching fonts.

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage{lmodern}     % for instance
\usepackage{amsmath}     % only for stuff in the last formula
\usepackage{amsfonts}    % ditto
\usepackage{complexity}
\makeatletter
% Define math alphabet \mathsfliti using LibertinusT1Math (adapted from
% libertinust1math.sty)
\unless\ifdefined\iflibus@sansmath
  \newif\iflibus@sansmath
\fi
\DeclareFontEncoding{LS1}{}{}
\DeclareFontSubstitution{LS1}{libertinust1math}{m}{n}
\DeclareMathAlphabet{\mathsfliti}{LS1}{libertinust1mathsf}{m}{n}
% Adapted from complexity.sty: use \mathsfliti for everything in complexity.sty
\renewcommand{\complexity@fontcommand}{\mathsfliti}
\renewcommand{\lang}[1]{{\ensuremath{\mathsfliti{#1}}}}
\renewcommand{\func}[1]{{\ensuremath{\mathsfliti{#1}}}}
\makeatother
\begin{document}
% \showoutput % Uncomment to verify which font is used for which glyph
[
   \begin{array}{l}
     \P \subseteq \NP\
     \CVP \leq_m \SAT\
     \polylog \in O(\poly)\
     \PSPACE \subseteq \EXP\
     \SAT \leq_T \MaxSAT\
     \polylog \in \Omega(\llog)
   \end{array}
]
\newcommand{\diff}{\mathop{}!d}% https://tex.stackexchange.com/a/84308/73317
[
  \forall z\in \mathbb{C},
    \Bigl(
      \Re(z) > 0 \implies \Gamma(z) =
        \int_{0}^{+\infty} x^{z-1} e^{-x} \diff x
    \Bigr)
]
\end{document}

score 1 · Accepted Answer · answered Jun 05 '22 at 20:38

The acmart class uses Linux Libertine fonts for text and does

\RequirePackage[libertine]{newtxmath}

If you do the same (with \usepackage, of course), you'll get what you want and avoid mixing visually incompatible fonts.

Using the code provided by frougon

\documentclass{article}
\usepackage{libertine}
\usepackage[libertine]{newtxmath}
\usepackage{amsmath}
\usepackage{complexity}
\begin{document}
[
   \begin{array}{l}
     \P \subseteq \NP\
     \CVP \leq_m \SAT\
     \polylog \in O(\poly)\
     \PSPACE \subseteq \EXP\
     \SAT \leq_T \MaxSAT\
     \polylog \in \Omega(\llog)
   \end{array}
]
\newcommand{\diff}{\mathop{}!d}% https://tex.stackexchange.com/a/84308/73317
[
  \forall z\in \mathbb{C},
    \Bigl(
      \Re(z) > 0 \implies \Gamma(z) =
        \int_{0}^{+\infty} x^{z-1} e^{-x} \diff x
    \Bigr)
]
\end{document}

This will use Linux Biolinum for the sans serif. If you want the sans serif used by libertinust1math, then you can do

\documentclass{article}
\usepackage{libertine}
\usepackage[libertine]{newtxmath}
\usepackage{amsmath}
\usepackage{complexity}
\DeclareFontEncoding{LS1}{}{}
\DeclareFontSubstitution{LS1}{libertinust1mathsf}{m}{n}
\DeclareMathAlphabet{\mathsf}{LS1}{libertinust1mathsf}{m}{n}
\SetMathAlphabet{\mathsf}{bold}{LS1}{libertinust1mathsf}{b}{n}
\begin{document}
[
   \begin{array}{l}
     \P \subseteq \NP\
     \CVP \leq_m \SAT\
     \polylog \in O(\poly)\
     \PSPACE \subseteq \EXP\
     \SAT \leq_T \MaxSAT\
     \polylog \in \Omega(\llog)
   \end{array}
]
\newcommand{\diff}{\mathop{}!d}% https://tex.stackexchange.com/a/84308/73317
[
  \forall z\in \mathbb{C},
    \Bigl(
      \Re(z) > 0 \implies \Gamma(z) =
        \int_{0}^{+\infty} x^{z-1} e^{-x} \diff x
    \Bigr)
]
\end{document}

Use libertine math font just for the complexity package

2 Answers2