A symbol after horizontal line

Question

I want to write this,

$\begin{tabular}{11}
A &is true \\ 
B &is true \\ 
\hline A \wedge B  &is true 
\end{tabular}$

How do add the "^I" after \hline?

Answer 1

You can use the ebproof package that offers much more.

\documentclass{article}
\usepackage{amsmath}
\usepackage{ebproof}
\begin{document}
[
\begin{prooftree}
\hypo{A \text{ true}}
\hypo{B \text{ true}}
\infer{2}[$\land I$]{A \land B \text{ true}}
\end{prooftree}
]
\end{document}

The argument {2} refers to the fact that you have two \hypo to typeset above the line.

Answer 2

We can use \over primitive for fractions:

$$ {\ \hbox{A true}\quad\hbox{B true}\ \over\hbox{A $\wedge$ B}}\wedge \rm I $$

Answer 3

Here's a LaTeX-based solution that employs a \frac expression.

\documentclass{article} % or some other suitable document class
\usepackage{amsmath}    % for '\text' macro
\begin{document}
\[
\frac{\text{$A$ true} \quad \text{$B$ true}}{%
      \text{$A\wedge B$ true}}
\wedge I
\]
\end{document}

Answer 4

\documentclass{article}
\usepackage{nicematrix}

\begin{document}

    \begin{table}
        \centering
        \NiceMatrixOptions{cell-space-limits = 3pt}

        \begin{NiceTabular}{ccc}

            A true                         & B true  &\Block{2-1}{$\wedge$ I}\\ \Hline
            \Block{1-2}{A $\wedge$ B true} &                                 \\
        \end{NiceTabular}

    \end{table}

\end{document}