arraysmissingtables
\documentclass{article}
\usepackage{amsmath}
\usepackage{amssymb}
\begin{document}
\begin{equation}
{S}=
\left(\begin{tabular}{1}
&\centering\{B_{M,i}\}\\
&\centering.\\
&\centering.\\
&\centering\{B_{1,i}\} \{B_{2,i}\} {.} {.} \{B_{M,i}\}
\end{tabular}
\right)
\end{equation}
\end{document}
When I execute the above code, I am getting the output, but it's stating "illegal character in an array arg".
The problem is that the \begin{...} and \end{...} pair commands automatically create a "group" so that, in effect, the & and \\ are "out of scope" for the tabular, while inside the "production" environment they just show up at a place where the compiler is not expecting them.
A second problem with your definitions is that, even if they would work, they would be adding an extra \\ at the end of the tabular, adding an unwanted space at the end. Perhaps some more appropriate definitions would be
\documentclass[a4paper,10pt]{article}
\newcommand{\production}[1]{#1 ::= &}
\newenvironment{grammar}{\tabular{p{3cm}l}}{\endtabular}
\begin{document}
\begin{grammar}
\production{XmlStartTag} ... \\
\production{XmlOtherTag} ... \\
\production{XmlEndTag} ...
\end{grammar}
\end{document}
Note no \\ at the end of the last production. Also in the definition of the grammar you don't need to repeat the work of \begin/\end, and you can instead directly use \tabular and \endtabular.
You want to avoid the \tabcolsep altogether; note also the correction for the null delimiter. You can use an optional argument to enlarge the leading in special cases.
\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{lmodern}
\usepackage{amsmath}
\newenvironment{system}[1][1.1]
{\renewcommand{\arraystretch}{#1}
\left\{\begin{array}{@{}l@{}}}
{\end{array}\right.\kern-\nulldelimiterspace}
\begin{document}
A centered formula for showing the center:
\[
\int_{-\infty}^{\infty}e^{-x^2}\,dx=\sqrt{\pi}
\]
The new \texttt{system} environment:
\[
\begin{system}
x^{n}+y^{n}=z^{n}\\
x^{m}+y^{m}=z^{m}
\end{system}
\]
Predefined \texttt{array} environment:
\[
\left\{%
\begin{array}{l}
x^{n}+y^{n}=z^{n}\\
x^{m}+y^{m}=z^{m}
\end{array}%
\right.
\]
A \texttt{system} environment with the optional argument:
\[
\begin{system}[1.5]
x^{n}+y^{n}=z^{n}\\
x^{m}+y^{m}=z^{m}
\end{system}
\]
\end{document}
Best Answer
The "illegal character in
arrayarg" references the fact that you're using1as a column specification which is undefined. You can only usel,r,corp{<len>}. Also, usingtabularplaces everything in text mode, which doesn't allow subscript/superscript without being in math mode. There isarrayas a math alternative.Here's a suggested solution: