Resumen: Let X be a complex Banach space. The connection between algebra homomorphisms defined on subalgebras of the Banach algebra l1(N0) and fractional versions of Ces`aro sums of a linear operator T € B(X) is established. In particular, we show that every (C,alpha)-bounded operator T induces an algebra homomorphism — and it is in fact characterized by such an algebra homomorphism. Our method is based on some sequence kernels, Weyl fractional difference calculus and convolution Banach algebras that are introduced and deeply examined. To illustrate our results, improvements to bounds for Abel means, new insights on the (C, alpha)-boundedness of the resolvent operator for temperated alpha-times integrated semigroups, and examples of bounded homomorphisms are given in the last section. Idioma: Inglés DOI: 10.1007/s11856-016-1417-3CES Año: 2016 Publicado en: Israel Journal of Mathematics 216, 1 (2016), 471-505 ISSN: 0021-2172 Factor impacto JCR: 0.796 (2016) Categ. JCR: MATHEMATICS rank: 105 / 310 = 0.339 (2016) - Q2 - T2 Factor impacto SCIMAGO: 1.487 - Mathematics (miscellaneous) (Q1)