Transform Piecewise[] into sum of indicators

Another option is to express Piecewise in terms of UnitStep.

In[1]:= f = Piecewise[{{x,3*x>y&&x<2*y},{y,2*x>y&&x<3*y}},0];

In[2]:= Simplify`PWToUnitStep[f]
Out[2]= x (1-UnitStep[x-2 y]) (1-UnitStep[-3 x+y])+
          y ((1-UnitStep[x-3 y]) UnitStep[x-2 y] (1-UnitStep[-2 x+y])+(1-UnitStep[x-3 y]) 
          UnitStep[-3 x+y] (1-UnitStep[-2 x+y])-(1-UnitStep[x-3 y])^2 UnitStep[x-2 y] 
          UnitStep[-3 x+y] (1-UnitStep[-2 x+y])^2)