2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/173339In this lecture some mathematical tools necessary for a proper description of the Heisenberg antiferromagnet are presented. We would like to point out differences between ferro- and antiferromagnetic cases of Heisenberg Hamiltonian for finite spin systems. The ground-state properties are discussed.RevTeX, 4 pagesMathematical PhysicsStrongly Correlated Electronstext