DeclareMathOperator not displayed in math font with Beamer

Question

I am writing a Beamer presentation using pdfLaTeX for the backend. I want to use Lato for the text and eulervm for the math font. However my operator Re is not displayed with the math font in the equations:

I don't think this is a duplicate of that question since I am not using XeTeX. Regardless, is that expected since I didn't pick a math font that blends beautifully with the text font? Otherwise, how can I sort this problem? I tried using \usefonttheme{professionalfonts} without effect.

MWE:

\documentclass{beamer}

\usepackage[utf8]{inputenc}
\usepackage[UKenglish]{babel}
\usepackage[default]{lato}
\usepackage{eulervm}

\usefonttheme[onlymath]{serif}

\DeclareMathOperator{\Rey}{Re}

\begin{document}

\begin{frame}
  \begin{block}{In block}
    \begin{equation*}
      x + y = z
    \end{equation*}
    \begin{equation*}
      \Rey = 1
    \end{equation*}
    In text \(\Rey = 1\)
  \end{block}
\end{frame}

\end{document}

Math operators are done in the roman style, whereas euler is an italic style. — Steven B. Segletes, Apr 07 '20 at 11:44
@StevenBSegletes eulervm also have upright parts normally. The beamer math setup is imo incomplete. Try a normal beamer doc with no extea font setup, explain why mathrm is not set to mathsf by default. Mathrm gives serifs in a setup where both text and math is sans serif. I've started using the sansserifmath package (I think that is the name and I think it gives a better default math setup for beamer, including setting mathrm to mathsf by default) — daleif, Apr 07 '20 at 12:01
As Mico mentioned in their deleted answer you probably need the professionalfonts setup when you change the fonts used by beamer. — daleif, Apr 07 '20 at 12:03
I mentioned I tried \usefonttheme{professionalfonts} @daleif unless you mean something else? — circuitbreaker, Apr 07 '20 at 12:12

frougon · Accepted Answer · 2020-04-07T13:53:20.587

Since \Rey is supposed to represent the Reynolds number, what about something like \mathinner{\mathnormal{R\mkern -1mu e}}? The \mkern -1mu ensures this doesn't look like a product between R and e. Maybe there is a better way to achieve this, but since these glyphs come from a math font, I'm not sure. The \mathinner ensures there is some space around the whole, as happens when one uses \left and \right.

\documentclass{beamer}
\usepackage[default]{lato}
\usepackage{eulervm}

\usefonttheme[onlymath]{serif}

\newcommand*{\Rey}{\mathinner{\mathnormal{R\mkern -1mu e}}}

\begin{document}

\begin{frame}
  \begin{block}{In block}
    \begin{equation*}
      x + y = z
    \end{equation*}
    \begin{equation*}
      \Rey = 1
    \end{equation*}
    \begin{equation*}
      x\Rey y = 2
    \end{equation*}
    In text: \(\Rey = 1\), $x\Rey y = 2$.
  \end{block}
\end{frame}

\end{document}

score 2 · Answer 2 · answered Apr 07 '20 at 15:27

Although the workaround solution of @frougon answers the issue, it seems there was another post mentioning that issue there, which reported a 'more consistent' solution which avoids mingling with the kerning using \DeclareSymbolFont:

\documentclass{beamer}

\usepackage[utf8]{inputenc}
\usepackage[UKenglish]{babel}

\usepackage[default]{lato}
\usepackage{eulervm}

\usefonttheme[onlymath]{serif}

\DeclareMathOperator{\Rey}{Re}

\DeclareSymbolFont{sfoperators}{U}{zeur}{m}{n}
\makeatletter
    \renewcommand{\operator@font}{\mathgroup\symsfoperators}
\makeatother

\begin{document}

\begin{frame}
  \begin{block}{In block}
    \begin{equation*}
      x + y = z R e
    \end{equation*}
    \begin{equation*}
      \Rey = 1
    \end{equation*}
    In text \(\Rey = 1\)
  \end{block}
\end{frame}

\end{document}

No, this would also modify how \sin or \log appear. – egreg Apr 07 '20 at 16:32 — egreg, Apr 07 '20 at 16:32
True! I've just checked on my minimal example. – circuitbreaker Apr 07 '20 at 17:17 — circuitbreaker, Apr 07 '20 at 17:17

DeclareMathOperator not displayed in math font with Beamer

2 Answers2