Resumen: This paper introduces the α-fractal Sobolev system of functions corresponding to Sobolev orthonormal system of functions. An approximation-related result similar to Weierstrass theorem is derived. It is shown that the set of α-fractal versions of Sobolev sums is dense and complete in the weighted Sobolev space Wr,2ρ(I). A Schauder basis and a Riesz basis of fractal type for the space Wr,2ρ(I) are found. The Fourier–Sobolev expansion of an α-fractal function fα corresponding to a certain set of interpolation points is presented. Moreover, some results on convergence of Fourier–Sobolev expansion of fα with respect to uniform norm and Sobolev norm are established. Idioma: Inglés DOI: 10.1142/S1793557122502035 Año: 2022 Publicado en: Asian-European Journal of Mathematics 15, 11 (2022) ISSN: 1793-5571 Factor impacto CITESCORE: 1.3 - Mathematics (Q3)