How center align two equations separated by a line

Question

I wanted to center align two logical equations that do not use "=" sign. I also want to separate the equations with a line. Currently I use aligned environment and midrule. Can the equations be center aligned instead of right aligned? The minimum working example is given below:

\documentclass[border=3mm,preview]{standalone}
\usepackage{amsmath}
\usepackage{booktabs}

\begin{document}

    \begin{equation*}
    \begin{aligned}
        \forall_{t \in firing} \quad \forall_{a \in t \bullet} \quad a \in AN\\
        \midrule
        \mu^\prime_{an} = (\mu_{an} - \bullet t) \cup a, \quad c(a) = 0 \\
    \end{aligned}
    \end{equation*}
\end{document}

Answer 1

You could replace the aligned environment with a gathered environment, which centers its contents line by line.

\documentclass[border=3mm,preview]{standalone}
\usepackage{amsmath}
\usepackage{booktabs}
\begin{document}
    \begin{equation*}
    \begin{gathered} % 'gathered' instead of 'aligned'
        \forall_{t \in \textit{firing}} \quad \forall_{a \in t \bullet} \quad a \in AN\\
        \midrule
        \mu^\prime_{an} = (\mu_{an} - \bullet t) \cup a, \quad c(a) = 0 
    \end{gathered}
    \end{equation*}
\end{document}

Answer 2

I hope you understand your question. I add my MWE centering two logical equations without equal sign and separate the equations with a line.

\documentclass[a4paper]{article}
\usepackage{amsmath,amssymb,booktabs}
\begin{document}

$\begin{array}{@{}c@{}}
\forall_{t\in\mathit{firing}} \quad \forall_{a\in t\bullet} \quad a\in AN \\
\specialrule{.05em}{1em}{0em}\\
\mu'_{an} = (\mu_{an} - \bullet t) \cup a, \quad c(a) = 0 \\[.5em]
\specialrule{.2em}{.1em}{.1em} % optional
\end{array}$

\end{document}