fractionsrules
I'm trying to display some axioms and operational rules with LaTeX.
Those are basically . They work quite well when used with frac, but it's not really nice, I'd like the fraction line to be a bit longer.
I know that sounds a bit vague, so here is a picture of what I am trying to achieve. I'm pretty sure that document has been typeset in LaTeX, so it should be doable.
Use either \Tfrac or \Dfrac (short for Text and Display style "equal fraction") in the following:
\documentclass{article}
\usepackage{amsmath}% http://ctan.org/pkg/amsmath
\usepackage{xcolor}% http://ctan.org/pkg/xcolor
\newcommand{\Tfrac}[2]{%
\ooalign{%
$\genfrac{}{}{1.2pt}1{#1}{#2}$\cr%
$\color{white}\genfrac{}{}{.4pt}1{\phantom{#1}}{\phantom{#2}}$}%
}
\newcommand{\Dfrac}[2]{%
\ooalign{%
$\genfrac{}{}{1.2pt}0{#1}{#2}$\cr%
$\color{white}\genfrac{}{}{.4pt}0{\phantom{#1}}{\phantom{#2}}$}%
}
\begin{document}
$f(x)=\Tfrac{1}{2}+\frac{1}{2}$
\end{document}
For a short course on \ooalign, see \subseteq + \circ as a single symbol (“open subset”).
Here is a slightly modified set of commands: \Efrac and \efrac. While both adjust their fraction size based on the math style automatically (using \mathchoice), the former is vertically higher (set based on the height of the two outer black fraction lines) than the latter (set based on the height of a regular fraction).
\documentclass{article}
\usepackage{amsmath}% http://ctan.org/pkg/amsmath
\usepackage{xcolor}% http://ctan.org/pkg/xcolor
\newcommand{\Efrac}[2]{%
\mathchoice
{\ooalign{%
$\genfrac{}{}{1.2pt}0{#1}{#2}$\cr%
$\color{white}\genfrac{}{}{.4pt}0{\phantom{#1}}{\phantom{#2}}$}}%
{\ooalign{%
$\genfrac{}{}{1.2pt}1{#1}{#2}$\cr%
$\color{white}\genfrac{}{}{.4pt}1{\phantom{#1}}{\phantom{#2}}$}}%
{\ooalign{%
$\genfrac{}{}{1.2pt}2{#1}{#2}$\cr%
$\color{white}\genfrac{}{}{.4pt}2{\phantom{#1}}{\phantom{#2}}$}}%
{\ooalign{%
$\genfrac{}{}{1.2pt}3{#1}{#2}$\cr%
$\color{white}\genfrac{}{}{.4pt}3{\phantom{#1}}{\phantom{#2}}$}}%
}
\newcommand{\efrac}[2]{%
\mathchoice
{\ooalign{%
$\genfrac{}{}{1.2pt}0{\hphantom{#1}}{\hphantom{#2}}$\cr%
$\color{white}\genfrac{}{}{.4pt}0{\color{black}#1}{\color{black}#2}$}}%
{\ooalign{%
$\genfrac{}{}{1.2pt}1{\hphantom{#1}}{\hphantom{#2}}$\cr%
$\color{white}\genfrac{}{}{.4pt}1{\color{black}#1}{\color{black}#2}$}}%
{\ooalign{%
$\genfrac{}{}{1.2pt}2{\hphantom{#1}}{\hphantom{#2}}$\cr%
$\color{white}\genfrac{}{}{.4pt}2{\color{black}#1}{\color{black}#2}$}}%
{\ooalign{%
$\genfrac{}{}{1.2pt}3{\hphantom{#1}}{\hphantom{#2}}$\cr%
$\color{white}\genfrac{}{}{.4pt}3{\color{black}#1}{\color{black}#2}$}}%
}
\begin{document}
\[ f(x)={\textstyle\Efrac{1}{2}+\frac{1}{2}} \sim \Efrac{3}{4}+\frac{3}{4} \]
\[ f(x)={\textstyle\efrac{1}{2}+\frac{1}{2}} \sim \efrac{3}{4}+\frac{3}{4} \]
\end{document}
I simply solved my problem with a \newcommand:
\newcommand{\thickfrac}[2]{\genfrac{}{}{3pt}{}{#1}{#2}}
Best Answer