Dtyjlui

I'd like to typeset a long bar symbol over an ordered pair like (g,epsilon). The best I could do so far is naif and really poor:

Is there a standard command for that?

Here there is a possible MWE code.

documentclass[a4paper,12pt]{article}

usepackage{amsmath,amssymb}

begin{document}

$overline{(g,epsilon)}$ or $(overline{g,epsilon})$

end{document}

The output is:

I propose either to use @Hendrik Vogt's solution, as an answer to a question of mine, or to use the widebar command, from mathabx, without loading the package. Here is a demo of both solutions:

documentclass{article}

usepackage{amsmath}



makeatletter % Hendrik Vogt's code

letsave@mathaccentmathaccent

newcommand*if@single[3]{%

  setbox0hbox{${mathaccent"0362{#1}}^H$}%

  setbox2hbox{${mathaccent"0362{kern0pt#1}}^H$}%

  ifdimht0=ht2 #3else #2fi

  }

%The bar will be moved to the right by a half of macc@kerna, which is computed by amsmath:

newcommand*rel@kern[1]{kern#1dimexprmacc@kerna}

%If there's a superscript following the bar, then no negative kern may follow the bar;

%an additional {} makes sure that the superscript is high enough in this case:

newcommand*widebar[1]{@ifnextchar^{{wide@bar{#1}{0}}}{wide@bar{#1}{1}}}

%Use a separate algorithm for single symbols:

newcommand*wide@bar[2]{if@single{#1}{wide@bar@{#1}{#2}{1}}{wide@bar@{#1}{#2}{2}}}

newcommand*wide@bar@[3]{%

  begingroup

  defmathaccent##1##2{%

%Enable nesting of accents:

    letmathaccentsave@mathaccent

%If there's more than a single symbol, use the first character instead (see below):

    if#32 letmacc@nucleusfirst@char fi

%Determine the italic correction:

    setboxz@hbox{$macc@style{macc@nucleus}_{}$}%

    setboxtw@hbox{$macc@style{macc@nucleus}{}_{}$}%

    dimen@wdtw@

    advancedimen@-wdz@

%Now dimen@ is the italic correction of the symbol.

    dividedimen@ 3

    @tempdimawdtw@

    advance@tempdima-scriptspace

%Now @tempdima is the width of the symbol.

    divide@tempdima 10

    advancedimen@-@tempdima

%Now dimen@ = (italic correction / 3) - (Breite / 10)

    ifdimdimen@>z@ dimen@0ptfi

%The bar will be shortened in the case dimen@<0 !

    rel@kern{0.6}kern-dimen@

    if#31

      overline{rel@kern{-0.6}kerndimen@macc@nucleusrel@kern{0.4}kerndimen@}%

      advancedimen@0.4dimexprmacc@kerna

%Place the combined final kern (-dimen@) if it is >0 or if a superscript follows:

      letfinal@kern#2%

      ifdimdimen@<z@ letfinal@kern1fi

      iffinal@kern1 kern-dimen@fi

    else

      overline{rel@kern{-0.6}kerndimen@#1}%

    fi

  }%

  macc@depth@ne

  letmath@bgroup@empty letmath@egroupmacc@set@skewchar

  mathsurroundz@ frozen@everymath{mathgroupmacc@grouprelax}%

  macc@set@skewcharrelax

  letmathaccentVmacc@nested@a

%The following initialises macc@kerna and calls mathaccent:

  if#31

    macc@nested@arelax111{#1}%

  else

%If the argument consists of more than one symbol, and if the first token is

%a letter, use that letter for the computations:

    defgobble@till@marker##1endmarker{}%

    futureletfirst@chargobble@till@marker#1endmarker

    ifcatnoexpandfirst@char Aelse

      deffirst@char{}%

    fi

    macc@nested@arelax111{first@char}%

  fi

  endgroup

}

makeatother



%%%% with mathabx (without loading it))



    DeclareFontFamily{U}{mathx}{hyphencharfont45}

    DeclareFontShape{U}{mathx}{m}{n}{

    <-6> mathx5 <6-7> mathx6 <7-8> mathx7

    <8-9> mathx8 <9-10> mathx9

    <10-12> mathx10 <12-> mathx12

    }{}

    DeclareSymbolFont{mathx}{U}{mathx}{m}{n}

    DeclareFontSubstitution{U}{mathx}{m}{n}

    DeclareMathAccent{varwidebar}{0}{mathx}{"73}



begin{document}



[ widebar{(g, varepsilon)} ]

[ varwidebar{(g, varepsilon)} ]



end{document}