2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/186946We study three-dimensional self-avoiding walks in presence of a one-dimensional excluded region. We show the appearance of a universal sub-leading exponent which is independent of the particular shape and symmetries of the excluded region. A classical argument provides the estimate: $Δ= 2 ν- 1 \approx 0.175(1)$. The numerical simulation gives $Δ= 0.18(2)$.29 pages, latex2eHigh Energy Physics - LatticeStatistical Mechanicstext