2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/64363An expression is given for the plethysm $p_{2}\circ S_{\square}$, where $p_{2}$ is the power sum of degree two and $S_{\square}$ is the Schur function indexed by a rectangular partition. The formula can be well understood from the viewpoint of the basic representation of the affine Lie algebra of type $A_{2}^{(2)}$.16 pagesCombinatoricsRepresentation Theory05E05; 17B65text