Dual model for parton densities

We derive power-counting rules for quark densities near $x=1\mathrm{}$ and $x=0\mathrm{}$ from parton interpretations of one-particle inclusive dual amplitudes. Using these rules, we give explicit expressions for quark distributions (including charm) inside hadrons. We can then show the compatibility between fragmentation and recombination descriptions of low-$p_{\perp }$ processes.