5

I am trying to align the right parentheses in a table using the tabular environment. The items in the list are labeled as "i.)", "ii.)", and "iii.)".

I am sure that this is more easily done using the tablists package, but I want to use the tabular environment.

\documentclass{article}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage[utf8]{inputenc}
\usepackage{mathtools,array}


\setlength{\oddsidemargin}{0.0in}
\setlength{\evensidemargin}{0.0in} \setlength{\textwidth}{6.1in}
\setlength{\topmargin}{0.0in} \setlength{\textheight}{9in}



\begin{document}

\noindent {\em $R$ is an integral domain.} \vskip1.25mm
\noindent\hspace{0.75em}
\begin{tabular}{@{}r@{}l}
\textbf{i.) }   &   {\em $r$ in a nonzero element of $R$ that is not a unit. It is \textbf{irreducible} in $R$ if, and only if, for} \\
                &   {\em every pair of elements $a$ and $b$ in $R$ such that $r = ab$, either $a$ or $b$ is a unit. It is \textbf{reduc-}} \\
                &   {\em \textbf{ible} in $R$ if, and only if, it is not irreducible.} \\
\textbf{ii.) }  &   {\em $p$ is a nonzero element of $R$ that is not a unit. It is \textbf{prime} in $R$ if, and only if, for every} \\
                &   {\em pair of elements $a$ and $b$ in $R$ such that $p \mid ab$, either $p \mid a$ or $p \mid b$.} \\
\textbf{iii.) } &   {\em $a$ and $b$ are \textbf{associates} in $R$ if, and only if, there is a unit $u \in R$ such that $a = ub$.}
\end{tabular}


\end{document}
2
  • 1
    The parentheses look aligned to me... – campa Jan 12 at 11:25
  • @campa At the time I had posted my concern about alignment, my editor was not implementing the code correctly. Now it does, and the right parentheses are aligned. – user74973 Feb 15 at 18:40
9
+50

You want a list, rather than a table.

\documentclass{article}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{mathtools,array}
\usepackage{enumitem}


\begin{document}

\emph{$R$ is an integral domain.}

\begin{enumerate}[label=\bfseries\roman*.)]
\item $r$ in a nonzero element of $R$ that is not a unit. It is \textbf{irreducible} in $R$ if,
  and only if, for every pair of elements $a$ and $b$ in $R$ such that $r = ab$, either $a$ or
  $b$ is a unit. It is \textbf{reducible} in $R$ if, and only if, it is not irreducible.

\item $p$ is a nonzero element of $R$ that is not a unit. It is \textbf{prime} in $R$ if,
  and only if, for every pair of elements $a$ and $b$ in $R$ such that $p \mid ab$, either
  $p \mid a$ or $p \mid b$.

\item $a$ and $b$ are \textbf{associates} in $R$ if, and only if, there is a unit $u \in R$
  such that $a = ub$.
\end{enumerate}

\end{document}

I'd not set the whole thing in italics, but it's your document.

enter image description here

I'm not sure why you're insisting on having an additional margin. However, here's how you can do it. I have to warn you that I find this very disputable, from a typographic point of view.

Long chunks of italic text are difficult to read; there's no need to use boldface for the labels; the additional margin serves no purpose, in my opinion. My starting point is that if something requires too many tricks to be achieved in LaTeX, it's likely to be typographically wrong.

\documentclass{article}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{mathtools,array}
\usepackage{enumitem}

\setlength{\oddsidemargin}{0.0in}
\setlength{\evensidemargin}{0.0in} \setlength{\textwidth}{6.1in}
\setlength{\topmargin}{0.0in} \setlength{\textheight}{9in}


\begin{document}

\section{Your output}

\noindent {\em $R$ is an integral domain.} \vskip1.25mm
\noindent\hspace{0.75em}
\begin{tabular}{@{}r@{}l}
\textbf{i.) }   &   {\em $r$ in a nonzero element of $R$ that is not a unit. It is \textbf{irreducible} in $R$ if, and only if, for} \\
                &   {\em every pair of elements $a$ and $b$ in $R$ such that $r = ab$, either $a$ or $b$ is a unit. It is \textbf{reduc-}} \\
                &   {\em \textbf{ible} in $R$ if, and only if, it is not irreducible.} \\
\textbf{ii.) }  &   {\em $p$ is a nonzero element of $R$ that is not a unit. It is \textbf{prime} in $R$ if, and only if, for every} \\
                &   {\em pair of elements $a$ and $b$ in $R$ such that $p \mid ab$, either $p \mid a$ or $p \mid b$.} \\
\textbf{iii.) } &   {\em $a$ and $b$ are \textbf{associates} in $R$ if, and only if, there is a unit $u \in R$ such that $a = ub$.}
\end{tabular}

\section{My output}

\noindent\emph{$R$ is an integral domain.}

\begin{enumerate}[label=\normalfont\bfseries\roman*.),topsep=1.25mm]
\setlength{\leftskip}{0.75em}\em
\item $r$ in a nonzero element of $R$ that is not a unit. It is \textbf{irreducible} in $R$ if, 
  and only if, for every pair of elements $a$ and $b$ in $R$ such that $r = ab$, either $a$ or 
  $b$ is a unit. It is \textbf{reducible} in $R$ if, and only if, it is not irreducible.

\item $p$ is a nonzero element of $R$ that is not a unit. It is \textbf{prime} in $R$ if,
  and only if, for every pair of elements $a$ and $b$ in $R$ such that $p \mid ab$, either
  $p \mid a$ or $p \mid b$.

\item $a$ and $b$ are \textbf{associates} in $R$ if, and only if, there is a unit $u \in R$ 
  such that $a = ub$.
\end{enumerate}


\end{document}

enter image description here

9
  • In Italian language is it a R a UFD or PID? :-) – Sebastiano Jan 12 at 12:56
  • 1
    The English abbreviations are commonly used. Note that every PID is a UFD, but not conversely. – egreg Jan 12 at 13:12
  • How do I get the indentation of `\hspace*{0.75em}'? – user74973 Jan 12 at 17:59
  • @user74973 Where did you get the 0.75em? – egreg Jan 12 at 18:13
  • In my post, immediately before the tabular environment, I have "\noindent\hspace{0.75em}". – user74973 Jan 13 at 10:09

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