4

For a logic assignment I need to do something that looks like the one in red:

wanted

I do know that I've not done a minimal work but I truly don't know how to do something like this. All I can think about is this code:

\begin{align*}
&\underbrace{\Gamma}_{\quad} \\
&\thinspace\thinspace\thinspace\thinspace\varphi \\ 
& -- \\
& \thinspace\thinspace\thinspace\thinspace p_0
\end{align*}

And it doesn't look good at all.

1
  • for the last part you can use $\frac{\varphi}{p_0}$. For the upper part I don't know Commented Oct 15, 2015 at 7:41

2 Answers 2

7

(UPDATED to include the picture as part of a formula)

Tikz is probably overkill for this, but easy to do:

\documentclass{standalone}
\usepackage{tikz}
\usepackage{amsmath}
\usetikzlibrary{positioning}

\begin{document}
\begin{equation*}
  \begin{tikzpicture}[baseline=(P.north)]
    \node (G) {$\Gamma$};
    \node[below=1.5ex of G] (P) {$\frac{\varphi}{p_0}$};
    \draw (G.east) -- (P.north) -- (G.west);
  \end{tikzpicture} 
  \in \text{DER}
\end{equation*}
\end{document}

Result

3

Done as a stack.

REVISED SOLUTION (with pointed vee and one less package):

\documentclass{article}
\usepackage{stackengine,graphicx}
\stackMath
\def\mystrut#1{\rotatebox[origin=c]{#1}{\rule{.4pt}{4ex}}}
\def\thinvee{\raisebox{-2pt}{\mystrut{45}\kern.8\dimexpr-.7071pt\mystrut{-45}}}
\begin{document}
\[
\stackunder[0pt]{\stackon[-4pt]{\thinvee}{\Gamma}}{\frac{\varphi}{~p_0~}}\in \textrm{DER}
\]
\end{document}

enter image description here

ORIGINAL SOLUTION:

\documentclass{article}
\usepackage{stackengine,graphicx,xcolor}
\stackMath
\def\myvee{\raisebox{2pt}{\scalebox{3}[1.3]{$\bigvee$}}}
\def\thinvee{\stackengine{.5pt}{\myvee}{\color{white}\myvee}{O}{c}{F}{F}{L}}
\begin{document}
\[
\stackunder{\stackon[-5pt]{\thinvee}{\Gamma}}{\frac{\varphi}{~p_0~}}\in \textrm{DER}
\]
\end{document}

enter image description here

5
  • 1
    i don't know whether the point on the vee is significant, but the rounding doesn't look quite like something a mathematician would produce. Commented Oct 15, 2015 at 14:58
  • @barbarabeeton Point taken, though it came from a scale of \bigvee. Commented Oct 15, 2015 at 14:59
  • the scaling alone doesn't cause such a distinct curve. i don't know stackengine well enough to understand what's happening, but from experiments with scaling only, it seems that the exaggeration results from the way the white is applied. with scaling only, the inner angle remains sharp. Commented Oct 15, 2015 at 15:10
  • @barbarabeeton Fixed. Commented Oct 15, 2015 at 15:10
  • much nicer after edit. Commented Oct 15, 2015 at 15:10

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