2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/28288We study a set of exactly soluble net spin models. There exist two kinds of ground state, one is a complete dimerized state, and the other one is the ground state of corresponding spin-1 model. For the excitation gap, various phases were discovered and determined.4 pages, 3 figures, replace cond-mat/9805269Condensed Mattertext