Sandbox

 
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 \theoremstyle{definition}
 \newtheorem{definition}{Definition}
 \newtheorem*{morphisms}{Morphisms}
 \newtheorem*{basic_results}{Basic Results}
 \newtheorem*{examples}{Examples}
 \newtheorem{example}{}
 \newtheorem*{properties}{Properties}
 \newtheorem*{finite_members}{Finite Members}
 \newtheorem*{subclasses}{Subclasses}
 \newtheorem*{superclasses}{Superclasses}
 \newcommand{\abbreviation}[1]{\textbf{Abbreviation: #1}}
 \pagestyle{myheadings}\thispagestyle{myheadings}
 \markboth{\today}{math.chapman.edu/structures}
 
 \begin{document}
 \begin{definition}
 A \emph{semigroup} is a structure $\mathbf{S}=\langle S,\cdot\rangle$ such that
 
   
 $\cdot$ is \emph{associative}:  $(x\cdot y)\cdot z=x\cdot (y\cdot z)$
 
   
 Remark: 
 Click on the 'Edit text of this page' link at the bottom, then make any changes you like and preview or save the page. 
 
 (This is just a shortened sample of the semigroups page. Feel free to try anything you like here.)
   
 \end{definition}
 
 \begin{table}[h]
 \begin{properties} (\href{http://math.chapman.edu/cgi-bin/structures?Properties}{description})
 
 \begin{tabular}{|ll|}\hline
   Classtype &   variety\\\hline
   Equational theory &   decidable\\\hline
 \end{tabular}
 \end{properties}
 \end{table}
 \begin{finite_members} $f(n)=$ number of members of size $n$.
 
 $\begin{array}{lr}
   f(1)= &1\\
   f(2)= &\\
   f(3)= &\\
 \end{array}$
 \end{finite_members}
 \hyperbaseurl{http://math.chapman.edu/structures/files/}
 \parskip0pt
 \begin{subclasses}\ 
 
   \href{Commutative_semigroups.pdf}{Commutative semigroups} 
 
 \end{subclasses}
 \begin{superclasses}\ 
 
   \href{Monoids.pdf}{Monoids} 
 
 \end{superclasses}
 
 \begin{thebibliography}{10}
 
 \bibitem{Ln19xx}
 
 \end{thebibliography}
 
 \end{document}
 %