Results 11 to 20 of about 135 (51)
On the domain of selfadjoint extension of the product of Sturm‐Liouville differential operators
International Journal of Mathematics and Mathematical Sciences, Volume 2003, Issue 11, Page 695-709, 2003., 2003 The second‐order symmetric Sturm‐Liouville differential expressions τ1, τ2, …, τn with real coefficients are considered on the interval I = (a, b), −∞ ≤ a < b ≤ ∞. It is shown that the characterization of singular selfadjoint boundary conditions involves the sesquilinear form associated with the product of Sturm‐Liouville differential expressions and ...
Sobhy El-Sayed Ibrahim
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USING PERTURBATION METHODS AND LAPLACE-PAD´ E APPROXIMATION TO SOLVE NONLINEAR PROBLEMS
, 2013 In this paper, the perturbation method and Padtransformation are used to provide an approximate solution of elliptic integrals of the second kind and of complete integrals of the first kind.
U. Filobello-Nino +7 more
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A spectral mapping theorem for semigroups solving PDEs with nonautonomous past
Abstract and Applied Analysis, Volume 2003, Issue 16, Page 933-951, 2003., 2003 We prove a spectral mapping theorem for semigroups solving partial differential equations with nonautonomous past. This theorem is then used to give spectral conditions for the stability of the solutions of the equations.
Genni Fragnelli
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Weyl's theorem and its perturbations for the functions of operators
, 2018 In this paper, we study the stability of Weyl’s theorem under compact perturbations, and characterize those operators satisfying that the stability of Weyl’s theorem does not hold for any integer powers of the operator. Mathematics subject classification
X. Cao, Jiong Dong, Jun Liu
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A Note on Property $(gb)$ and Perturbations [PDF]
, 2012 An operator T ∈ B(X) defined on a Banach space X satisfies property (gb) if the complement in the approximate point spectruma(T) of the upper semi-B-Weyl spectrumSBF + (T) coincides with the set (T) of all poles of the resolvent of T.
Qingping Zeng, H. Zhong
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Kreĭn′s trace formula and the spectral shift function
International Journal of Mathematics and Mathematical Sciences, Volume 25, Issue 4, Page 239-252, 2001., 2001 Let A, B be two selfadjoint operators whose difference B − A is trace class. Kreĭn proved the existence of a certain function ξ ∈ L1(ℝ) such that tr[f(B) − f(A)] = ∫ℝf′(x)ξ(x)dx for a large set of functions f. We give here a new proof of this result and discuss the class of admissible functions.
Khristo N. Boyadzhiev
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Evolution semigroups for nonautonomous Cauchy problems
Abstract and Applied Analysis, Volume 2, Issue 1-2, Page 73-95, 1997., 1997 In this paper, we characterize wellposedness of nonautonomous, linear Cauchy problems on a Banach space X by the existence of certain evolution semigroups. Then, we use these generation results for evolution semigroups to derive wellposedness for nonautonomous Cauchy problems under some “concrete” conditions.
Gregor Nickel
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A bound for the Hilbert-Schmidt norm of generalized commutators of nonself-adjoint operators
, 2017 Let A, à and B be bounded linear operators in a Hilbert space, and f (z) be a function regular on the convex hull of the union of the spectra of A and à . Let SN2 be the ideal of Hilbert-Schmidt operators.
M. Gil'
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Iterative solution of unstable variational inequalities on approximately given sets
Abstract and Applied Analysis, Volume 1, Issue 1, Page 45-64, 1996., 1996 The convergence and the stability of the iterative regularization method for solving variational inequalities with bounded nonsmooth properly monotone (i.e., degenerate) operators in Banach spaces are studied. All the items of the inequality (i.e., the operator A, the “right hand side” f and the set of constraints Ω) are to be perturbed. The connection
Y. I. Alber, A. G. Kartsatos, E. Litsyn
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Bifurcation for the solutions of equations involving set valued mappings
International Journal of Mathematics and Mathematical Sciences, Volume 8, Issue 1, Page 37-48, 1985., 1985 This paper is devoted to a generalization of the bifurcation theorem of Karsnosel′skii and Rabinowitz to the set valued situation.
E. U. Tarafdar, H. B. Thompson
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