On the closedness, the self-adjointness and the normality of the product of two unbounded operators

• Autorzy: Mortad M. H.
• Języki publikacji: PL

Abstrakty

EN

Let A and B be two unbounded densely defined operators on a Hilbert space H . The purpose of this work is to give simple conditions that make the product AB closed, self-adjoint and normal provided the two operators are so.

Słowa kluczowe

EN

unbounded operators; closed; self-adjoint and normal opera-tors; product of operators; commutativity; relative boundedness

• Wydawca: De Gruyter
• Czasopismo: Demonstratio Mathematica
• Rocznik: 2012
• Tom: Vol. 45, nr 1
• Strony: 161--167
• Opis fizyczny: Bibliogr. 11 poz.

Twórcy

autor

Mortad M. H.

• Departement De Mathematiques Universite D'oran B.P. 1524, El Menouar Oran 31000, Algeria,

Bibliografia

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• [3] B. Messirdi, M. H. Mortad, A. Azzouz, G. Djellouli, A topological characterization of the product of two closed operators, Colloq. Math. 112 (2008), 269–278.
• [4] M. H. Mortad, An application of the Putnam–Fuglede theorem to normal products of self-adjoint operators, Proc. Amer. Math. Soc. 131 (2003), 3135–3141.
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• [6] M. H. Mortad, On the adjoint and the closure of the sum of two unbounded operators, Canad. Math. Bull. 54 (2011), 498–505. DOI:10.4153/CMB-2011-041-7.
• [7] M. H. Mortad, On the normality of the sum of two normal operators, Complex Anal. Oper. Theory 6 (2012), 105–112. DOI: 10.1007/s11785-010-0072-7.
• [8] M. Reed, B. Simon, Methods of modern mathematical physics, Vol. 1: Functional Analysis, Academic Press, 1972.
• [9] M. Reed, B. Simon, Methods of modern mathematical physics, Vol. 2: Fourier Analysis, Self-Adjointness, Academic Press, 1975.
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