  We consider the partially asymmetric simple exclusion process (PASEP) when
its steady-state probability distribution function can be written in terms of a
linear superposition of product measures with a finite number of shocks. In
this case the PASEP can be mapped into an equilibrium walk model, defined on a
diagonally rotated square lattice, in which each path of the walk model has
several transits with the horizontal axis. We particularly show that the
multiple-point density correlation function in the PASEP is related to the
probability that a path has multiple contacts with the horizontal axis from the
above or below.
