 \leopard\elephant\partial _{{\rm a}}\partial ^{{\rm a}}X_\mu =%%TCIMACRO{\dfrac 12 }%BeginExpansion{\displaystyle {1 \over 2}}%EndExpansionh_{{\rm cd}}\partial _{{\rm a}}h^{{\rm cd}}\partial ^{{\rm a}}X_\mu .\label{v.17}