2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/70782We establish the eventual periodicity of the spectrum of any monadic second-order formula where: (i) all relation symbols, except equality, are unary, and (ii) there is only one function symbol and that symbol is unary.LogicSpectra of Monadic Second-Order Formulas with One Unary Functiontext