Spectral decomposition and Gelfand's theorem

dc.creatorDriouich, A.
dc.creatorEl-Mennaoui, O.
dc.creatorJazar, M.
dc.date2005-05-20
dc.date2007-10-31
dc.date.accessioned2026-07-07T08:39:33Z
dc.date.available2026-07-07T08:39:33Z
dc.descriptionIn this paper we are interested in spectral decomposition of an unbounded operator with discrete spectrum. We show that if $A$ generates a polynomially bounded $n$-times integrated group whose spectrum set $σ(A)=\{iλ_k; k\in\mathbb{Z}^* \}$ is discrete and satisfies $\sum \frac{1}{|λ_k|^\ellδ_k^n}<\infty$ ($n$ and $\ell$ nonnegative integers), then there exists projectors $(P_k)_{k\in\mathbb{Z}^*}$ such that $\sum P_kx=x$ ($ x\in D(A^{n+\ell})$), where $δ_k=\min(\frac{| λ_{k+1}-λ_k|}2, \frac{|λ_{k-1}-λ_k|}2)$.
dc.description15 pages, 1 figure
dc.identifierhttps://arxiv.org/abs/math/0505428
dc.identifierhttp://arxiv.org/abs/math/0505428
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/141111
dc.subjectSpectral Theory
dc.subject47A60, 47A10, 47D03, 47D06, 47D62 (Primary) 47A10 (Secondary)
dc.titleSpectral decomposition and Gelfand's theorem
dc.typetext

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