Same vertical alignment of equations in different cells inside a table

Question

I am trying to maintain the uniformity of equations living in different cells inside a table. Here is the code:

\begin{center}
\begin{tabular}{|c|c|c|}
\hline
 $Y^{2}B^{2}$ & $Z^{2}\chi^{2}$ & $X^{2}\lambda^{2}$ \\ \hline
 $\mathcal{O}_{1} = \mathrm{wc}_{1}(\partial_{\mu}A_{\nu}-\partial_{\nu}A_{\mu})(\partial^{\mu}A^{\nu}-\partial^{\nu}A^{\mu})$ & $\mathcal{O}_{7}= \mathrm{wc}_{7}Z^{\mu\nu}Z_{\mu}(\phi^{\dagger}\phi)^{2}$ & $\mathcal{O}_{9} = \gamma^{\mu}\gamma^{\nu}+\gamma^{\nu}\gamma^{\mu}$ \\ \hline
 $\mathcal{O}_{2} = \mathrm{wc}_{2} X^{\mu}X_{\mu}B^{\rho\sigma}B_{\rho\sigma}$ & $\mathcal{O}_{8} = \mathrm{wc}_{8}\bar{\psi}(i\gamma^{\mu}\partial_{\mu}-m)\psi-\frac{1}{4}F_{\mu\nu}F^{\mu\nu}$ & $\mathcal{O}_{10} = g^{\mu\nu}$ \\ \hline
\end{tabular}
\end{center}

It looks like a mess because of poor alignment. In addition to that, the expressions are very close to each other makes the equations unreadable. Can anyone guide me on how to fix these two issues:

1. Same alignment for all expressions living in different cells.
2. Optimizing the cell size to make expressions readable.

Answer 1

Do you mean something like this:

\begin{center}
\renewcommand{\arraystretch}{1.5}
\begin{tabular}{|l|l|l|}
\hline
 \multicolumn{1}{|c|}{$Y^{2}B^{2}$} &  \multicolumn{1}{c|}{$Z^{2}\chi^{2}$} &  \multicolumn{1}{c|}{$X^{2}\lambda^{2}$} \\ \hline
 $\mathcal{O}_{1} = \mathrm{wc}_{1}(\partial_{\mu}A_{\nu}-\partial_{\nu}A_{\mu})(\partial^{\mu}A^{\nu}-\partial^{\nu}A^{\mu})$ & $\mathcal{O}_{7}= \mathrm{wc}_{7}Z^{\mu\nu}Z_{\mu}(\phi^{\dagger}\phi)^{2}$ & $\mathcal{O}_{9} = \gamma^{\mu}\gamma^{\nu}+\gamma^{\nu}\gamma^{\mu}$ \\ \hline
 $\mathcal{O}_{2} = \mathrm{wc}_{2} X^{\mu}X_{\mu}B^{\rho\sigma}B_{\rho\sigma}$ & $\mathcal{O}_{8} = \mathrm{wc}_{8}\bar{\psi}(i\gamma^{\mu}\partial_{\mu}-m)\psi-\frac{1}{4}F_{\mu\nu}F^{\mu\nu}$ & $\mathcal{O}_{10} = g^{\mu\nu}$ \\ \hline
\end{tabular}
\end{center}

?

Answer 2

Stll another variant: I replaced \arraystretch with some vertical padding at the top and bottom of cells obtained with the cellspace package. Another small improvement is the use of the medsize fractions n defined by nccmath, to avoid the size discrepancy between fractions in a tabular or array environment and the rest of the formula.

\documentclass{article}
\usepackage[hmargin=2.5cm]{geometry}
\usepackage{nccmath}
\usepackage{array}
\usepackage[column=O, math]{cellspace}
\setlength{\cellspacetoplimit}{4pt}
\setlength{\cellspacebottomlimit}{4pt}

\begin{document}

\[
\begin{tabular}{|*{3}{>{$}Ol<{$}|}}
\hline
 \multicolumn{1}{|c|}{$ Y^{2}B^{2} $}
   & \multicolumn{1}{c|}{$ Z^{2}\chi^{2} $}
     & \multicolumn{1}{c|}{$ X^{2}\lambda^{2} $} \\ \hline
 \mathcal{O}_{1} = \mathrm{wc}_{1}(\partial_{\mu}A_{\nu}-\partial_{\nu}A_{\mu})(\partial^{\mu}A^{\nu}-\partial^{\nu}A^{\mu}) & \mathcal{O}_{7}= \mathrm{wc}_{7}Z^{\mu\nu}Z_{\mu}(\phi^{\dagger}\phi)^{2}
 & \mathcal{O}_{9\phantom{1}} = \gamma^{\mu}\gamma^{\nu}+\gamma^{\nu}\gamma^{\mu} \\
\hline
 \mathcal{O}_{2} = \mathrm{wc}_{2} X^{\mu}X_{\mu}B^{\rho\sigma}B_{\rho\sigma}
 & \mathcal{O}_{8} = \mathrm{wc}_{8}\bar{\psi}(i\gamma^{\mu}\partial_{\mu}-m)\psi-\mfrac{1}{4}F_{\mu\nu}F^{\mu\nu}
 & \mathcal{O}_{10} = g^{\mu\nu} \\
\hline
\end{tabular}
\]

\end{document} 

Answer 3

Building upon koleygr's code, here is a slightly different version using an array instead of a tabular and \phantom to improve the alignment of the = in the last column:

\documentclass{article}
\usepackage[margin=2cm]{geometry}
\begin{document}

\[
\renewcommand{\arraystretch}{1.5}
\begin{array}{|l|l|l|}
\hline
 \multicolumn{1}{|c|}{Y^{2}B^{2}} 
   &  \multicolumn{1}{c|}{Z^{2}\chi^{2}} 
     &  \multicolumn{1}{c|}{X^{2}\lambda^{2}} \\ \hline
 \mathcal{O}_{1} = \mathrm{wc}_{1}(\partial_{\mu}A_{\nu}-\partial_{\nu}A_{\mu})(\partial^{\mu}A^{\nu}-\partial^{\nu}A^{\mu}) & \mathcal{O}_{7}= \mathrm{wc}_{7}Z^{\mu\nu}Z_{\mu}(\phi^{\dagger}\phi)^{2} 
 & \mathcal{O}_{9\phantom{1}} = \gamma^{\mu}\gamma^{\nu}+\gamma^{\nu}\gamma^{\mu} \\ 
\hline
 \mathcal{O}_{2} = \mathrm{wc}_{2} X^{\mu}X_{\mu}B^{\rho\sigma}B_{\rho\sigma} 
 & \mathcal{O}_{8} = \mathrm{wc}_{8}\bar{\psi}(i\gamma^{\mu}\partial_{\mu}-m)\psi-\frac{1}{4}F_{\mu\nu}F^{\mu\nu} 
 & \mathcal{O}_{10} = g^{\mu\nu} \\ 
\hline
\end{array}
\]
\end{document}

---

Update:

In order to increase the horizontal space between the text and a vertical line, you can adjust the value of \arraycolsep to suit your needs. To change the vertical space between the text and a horizontal line, you could use \setcellgapes from the makecell package. The following MWE contains three somewhat exaggerated examples to show the effect of the two commands:

\documentclass{article}
\usepackage[margin=2cm]{geometry}

\usepackage{makecell}
\begin{document}

\[
\renewcommand{\arraycolsep}{10pt}
\setcellgapes{\arraycolsep}
\makegapedcells
\begin{array}{|l|l|l|}
\hline
 \multicolumn{1}{|c|}{Y^{2}B^{2}} 
   &  \multicolumn{1}{c|}{Z^{2}\chi^{2}} 
     &  \multicolumn{1}{c|}{X^{2}\lambda^{2}} \\ \hline
 \mathcal{O}_{1} = \mathrm{wc}_{1}(\partial_{\mu}A_{\nu}-\partial_{\nu}A_{\mu})(\partial^{\mu}A^{\nu}-\partial^{\nu}A^{\mu}) & \mathcal{O}_{7}= \mathrm{wc}_{7}Z^{\mu\nu}Z_{\mu}(\phi^{\dagger}\phi)^{2} 
 & \mathcal{O}_{9\phantom{1}} = \gamma^{\mu}\gamma^{\nu}+\gamma^{\nu}\gamma^{\mu} \\ 
\hline
 \mathcal{O}_{2} = \mathrm{wc}_{2} X^{\mu}X_{\mu}B^{\rho\sigma}B_{\rho\sigma} 
 & \mathcal{O}_{8} = \mathrm{wc}_{8}\bar{\psi}(i\gamma^{\mu}\partial_{\mu}-m)\psi-\frac{1}{4}F_{\mu\nu}F^{\mu\nu} 
 & \mathcal{O}_{10} = g^{\mu\nu} \\ 
\hline
\end{array}
\]

\[
\renewcommand{\arraycolsep}{5pt}
\setcellgapes{20pt}
\makegapedcells
\begin{array}{|l|l|l|}
\hline
 \multicolumn{1}{|c|}{Y^{2}B^{2}} 
   &  \multicolumn{1}{c|}{Z^{2}\chi^{2}} 
     &  \multicolumn{1}{c|}{X^{2}\lambda^{2}} \\ \hline
 \mathcal{O}_{1} = \mathrm{wc}_{1}(\partial_{\mu}A_{\nu}-\partial_{\nu}A_{\mu})(\partial^{\mu}A^{\nu}-\partial^{\nu}A^{\mu}) & \mathcal{O}_{7}= \mathrm{wc}_{7}Z^{\mu\nu}Z_{\mu}(\phi^{\dagger}\phi)^{2} 
 & \mathcal{O}_{9\phantom{1}} = \gamma^{\mu}\gamma^{\nu}+\gamma^{\nu}\gamma^{\mu} \\ 
\hline
 \mathcal{O}_{2} = \mathrm{wc}_{2} X^{\mu}X_{\mu}B^{\rho\sigma}B_{\rho\sigma} 
 & \mathcal{O}_{8} = \mathrm{wc}_{8}\bar{\psi}(i\gamma^{\mu}\partial_{\mu}-m)\psi-\frac{1}{4}F_{\mu\nu}F^{\mu\nu} 
 & \mathcal{O}_{10} = g^{\mu\nu} \\ 
\hline
\end{array}
\]

\[
\renewcommand{\arraycolsep}{20pt}
\setcellgapes{5pt}
\makegapedcells
\begin{array}{|l|l|l|}
\hline
 \multicolumn{1}{|c|}{Y^{2}B^{2}} 
   &  \multicolumn{1}{c|}{Z^{2}\chi^{2}} 
     &  \multicolumn{1}{c|}{X^{2}\lambda^{2}} \\ \hline
 \mathcal{O}_{1} = \mathrm{wc}_{1}(\partial_{\mu}A_{\nu}-\partial_{\nu}A_{\mu})(\partial^{\mu}A^{\nu}-\partial^{\nu}A^{\mu}) & \mathcal{O}_{7}= \mathrm{wc}_{7}Z^{\mu\nu}Z_{\mu}(\phi^{\dagger}\phi)^{2} 
 & \mathcal{O}_{9\phantom{1}} = \gamma^{\mu}\gamma^{\nu}+\gamma^{\nu}\gamma^{\mu} \\ 
\hline
 \mathcal{O}_{2} = \mathrm{wc}_{2} X^{\mu}X_{\mu}B^{\rho\sigma}B_{\rho\sigma} 
 & \mathcal{O}_{8} = \mathrm{wc}_{8}\bar{\psi}(i\gamma^{\mu}\partial_{\mu}-m)\psi-\frac{1}{4}F_{\mu\nu}F^{\mu\nu} 
 & \mathcal{O}_{10} = g^{\mu\nu} \\ 
\hline
\end{array}
\]


\end{document}