\begin{frame} \frametitle{Properties of Relations} \begin{goal}{Properties of a relation $R$} \vspace{-2ex} \begin{eqnarray*} \pause \text{\emph{Reflexive}} && \myall{x}{R(x,x)} \\ \pause \text{\emph{Symmetric}} && \myall{x}{\myall{y}{\big(\;R(x,y) \to R(y,x)\;\big)}} \\ \pause \text{\emph{Transitive}} && \myall{x}{\myall{y}{\myall{z}{\big(\;(R(x,y) \wedge R(y,z)) \to R(x,z)\;\big)}}} \\ \pause \text{\emph{Serial}} && \myall{x}{\myex{y}{R(x,y)}} \\ \pause \text{\emph{Functional}} && \myall{x}{\myex{y}{\big(\; R(x,y) \wedge \myall{z}{(R(x,z) \to z=y)}\;\big)}} \end{eqnarray*} \vspace{-2ex} \end{goal} \pause \begin{goal}{} An \emph{equivalence relation} is a relation that is \begin{itemize} \item reflexive, \item symmetric and \item transitive. \end{itemize} \end{goal} \end{frame}