2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/15969The effects of rare regions on the critical properties of quantum antiferromagnets with hidden degrees of freedom within the renormalization group is discussed. It is shown that for ``constrained'' systems the stability range on the phase diagram remains the same as in the mean-field theory while for ``unconstrained'' systems the stability range is effectively decreased.12 pages, latex, 4 figures; to appear in Physica ADisordered Systems and Neural Networkstext