<math> <piecewise> <piece> <apply><minus/><ci>x</ci></apply> <apply><lt/><ci> x</ci><cn> 0</cn></apply> </piece> <piece> <cn>0</cn> <apply><eq/><ci>x</ci><cn>0</cn></apply> </piece> <piece> <ci>x</ci> <apply><gt/><ci>x</ci><cn>0</cn></apply> </piece> </piecewise> </math>