2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/50816We consider the effects of homogeneous Dirichlet's boundary conditions on two infinite parallel plane surfaces separated by a small distance {\it a}. We find that although spontaneous symmetry breaking does not occur for the theory of a massless, quartically self-interacting real scalar field, the theory becomes a theory of a massive scalar field.10 pages; added remarks for section 3, references removed and others added, second term of Eq.(15) changedHigh Energy Physics - Theorytext