\begin{frame}
  \frametitle{Combinatory Logic (CL)}
  \small

  \begin{block}{}
  \begin{center}
  \(
  \begin{array}{lcl}
  \rule[1ex]{0ex}{2ex}
  Ap(Ap(Ap (S,x),y),z) & \to & Ap(Ap(x,z), Ap(y,z))\\
  Ap(Ap(K,x),y)&\to&  x\\
  Ap (I,x)&\to&  x
  \rule[-2ex]{0ex}{2ex}
  \end{array}\)
  \end{center}
  \end{block}

  \onslide<2->
  \begin{block}{CL in \alert<2>{infix notation}}
  \begin{center}
  \(\begin{array}{lcl}
  \rule[1ex]{0ex}{2ex}
  (((S\cdot x)\cdot y)\cdot z) &\to&((x\cdot z)\cdot(y\cdot z))\\
    ((K\cdot x)\cdot y) & \to&   x\\
  (I\cdot x)& \to&   x   \rule[-2ex]{0ex}{2ex}
  \end{array}\)
  \end{center}
  \end{block}
    
  \onslide<3-> 
  \begin{block}{CL in \alert<3>{standard notation}}
  \begin{center}
  \(\begin{array}{lcl}
  \rule[1ex]{0ex}{2ex} 
     Sxyz &\to&xz(yz)\\
    Kxy &\to  &x\\
     Ix &\to  &x
  \rule[-2ex]{0ex}{2ex}
  \end{array}\)
  \end{center}
  \end{block}

\end{frame}