Tagged nuclear structure functions with $HERMES$
  The production of slow nucleons in semi-inclusive deep inelastic electron scattering off nuclei, $A(e, e'N)X$, is analyzed for kinematical conditions accessible at $HERA$ with the $HERMES$ detector. The sensitivity of the semi-inclusive cross section to possible medium-dependent modifications of the nucleon structure function is illustrated. 
Silvano Simula (INFN - Sezione Sanita')