000130798 001__ 130798 000130798 005__ 20251113150202.0 000130798 0247_ $$2doi$$a10.1007/s43037-020-00114-6 000130798 0248_ $$2sideral$$a122483 000130798 037__ $$aART-2021-122483 000130798 041__ $$aeng 000130798 100__ $$0(orcid)0000-0003-2453-7841$$aAbadias, L.$$uUniversidad de Zaragoza 000130798 245__ $$aFunctional models up to similarity and a-contractions 000130798 260__ $$c2021 000130798 5203_ $$aWe study the generalization of m-isometries and m-contractions (for positive integers m) to what we call a-isometries and a-contractions for positive real numbers a. We show that an operator satisfying a certain inequality in hereditary form is similar to a-contraction. This improvement of [9, Theorem I] is based on some Banach algebras techniques. We show that our operator classes are closely connected with fractional finite differences. Using this techniques, we get that, given 0 < b< a, an a-contraction need not to be a b-contraction in general, but is a b-contraction if a natural additional requirement is imposed. 000130798 536__ $$9info:eu-repo/grantAgreement/ES/DGA-FEDER/E26-17R$$9info:eu-repo/grantAgreement/ES/MINECO-MCIU/PID2019-105979GB-I00 000130798 540__ $$9info:eu-repo/semantics/openAccess$$aAll rights reserved$$uhttp://www.europeana.eu/rights/rr-f/ 000130798 590__ $$a1.197$$b2021 000130798 591__ $$aMATHEMATICS$$b114 / 333 = 0.342$$c2021$$dQ2$$eT2 000130798 591__ $$aMATHEMATICS, APPLIED$$b166 / 267 = 0.622$$c2021$$dQ3$$eT2 000130798 592__ $$a0.554$$b2021 000130798 593__ $$aAnalysis$$c2021$$dQ2 000130798 593__ $$aAlgebra and Number Theory$$c2021$$dQ2 000130798 594__ $$a1.6$$b2021 000130798 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion 000130798 700__ $$0(orcid)0000-0001-6249-9247$$aBello, G. 000130798 700__ $$aYakubovich, D. 000130798 7102_ $$12006$$2015$$aUniversidad de Zaragoza$$bDpto. Matemáticas$$cÁrea Análisis Matemático 000130798 773__ $$g15, 2 (2021), 34 [29 pp]$$pBanach Journal of Mathematical Analysis$$tBanach Journal of Mathematical Analysis$$x2662-2033 000130798 8564_ $$s4052840$$uhttps://zaguan.unizar.es/record/130798/files/texto_completo.pdf$$yVersión publicada 000130798 8564_ $$s1063527$$uhttps://zaguan.unizar.es/record/130798/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada 000130798 909CO $$ooai:zaguan.unizar.es:130798$$particulos$$pdriver 000130798 951__ $$a2025-11-13-15:00:39 000130798 980__ $$aARTICLE