2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/60285We obtain an anlogue of Wigner's classical theorem on symmetries for Banach spaces. The proof is based on a result from the theory of linear preservers. Moreover, we present two other Wigner-type results for finite dimensional linear spaces over general fields.7 pages. To appear in Publ. Math. (Debrecen)Functional AnalysisRings and Algebras47N50text