2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/151902We present a set of coupled continuum equationswith a specific coupling between mobile grains $ρ$ and clusters $h$ on the surface of a sandpile. The equations are analysed self-consistently; we demonstrate that Edwards' infrared divergence is responsible for the unexpected critical exponents we find, which are verified by simulations.4 pages (revtex), 6 figuresStatistical Mechanicstext