((x \overset{A}{\Uparrow} ~y \overset{B}{\underset{A}{\Uparrow}}) \overset{B}{\Uparrow} ~z \overset{C}{\underset{B}{\Uparrow}}) \overset{C}{\Uparrow} | ((x \overset{A}{\Uparrow} ~y \overset{B}{\underset{A}{\Uparrow}}) \overset{B}{\Uparrow} ~z \overset{C}{\underset{B}{\Uparrow}}) \overset{C}{\Uparrow} |