Martínez Ansemil, José MaríaAron, Richard M.Ponte Miramontes, María Del Socorro2023-06-202023-06-2020121222-9016https://hdl.handle.net/20.500.14352/43946In this work we investigate the inverse approximation problems in the Lebesgue and Smirnov spaces with weights satisfying the so-called Muckenhoupt's Ap condition in terms of the -th mean modulus of smoothness, > 0. We obtain a converse theorem of trigonometric approximation in the weighted Lebesgue spaces and obtain some converse theorems of algebraic polynomial approximation in the weighted Smirnov spaces.engjournal articlehttp://math.ubbcluj.ro/~mathjour/index.htmlrestricted access517.98Weighted Smirnov spacesDini-smooth curveInverse theoremsFractional modulus of smoothness.Geometría diferencialFunciones (Matemáticas)1204.04 Geometría Diferencial1202 Análisis y Análisis Funcional