The size of the shock-layer governed by a conservation law is studied.
The conservation law is a parabolic reaction-convection-diffusion equ
ation with a small parameter multiplying the diffusion term and convex
flux. Rigorous upper and lower bounding functions for the solution of
the conservation law are established based on maximum-principle argum
ents. The bounding functions demonstrate that the size of the shock-la
yer is proportional to the parameter multiplying the diffusion term.