Active width at a slanted active boundary in directed percolation

The width W of the active region around an active moving wall in a directed percolation process diverges at the percolation threshold p(c) as W similar or equal to A epsilon(-nu)parallel to ln(epsilon(0)/epsilon), with epsilon=p(c)-p, epsilon(0) a constant, and nu(parallel to) = 1.734 the critical exponent of the characteristic time needed to reach the stationary state xi(parallel to)similar to epsilon(-nu)parallel to The logarithmic factor arises from screening the statistically independent needle shaped subclusters in the active region. Numerical data confirm this scaling behavior. [S1063-651X(99)00509-7].