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Parcourir Publications scientifiques par auteur "Messirdi, Bekkai"

Parcourir Publications scientifiques par auteur "Messirdi, Bekkai"

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  • Asymptotic analysis for Schrödinger Hamiltonians via Birkhoff–Gustavson normal form 
    Messirdi, Bekkai; Ghomari, Kaoutar; Vũ Ngọc, San (Asymptotic Analysis, 2013-01-01)
    This article reviews the Birkhoff–Gustavson normal form theorem (BGNF) near an equilibrium point of a quantum Hamiltonian. The BGNF process is thereafter used to investigate the spectrum of Schrödinger operators in the 1: ...
  • Asymptotique de Born-Oppenheimer pour la prédissociation moléculaire (cas de potentiels réguliers) 
    Messirdi, Bekkai (Annales de l'IHP Physique théorique, 1994)
    On étudie l’opérateur P=-h2 Ox-Dy+ Y (x,~/) sur R~ x R~ lorsque h tend vers 0, et V est un potentiel régulier. On se place dans un cas où deux niveaux électroniques se croisent dans la zone classiquement interdite, et où ...
  • -boundedness and-compactness of a class of Fourier integral operators. 
    Messirdi, Bekkai; Senoussaoui, Abderrahmane (Electronic Journal of Differential Equations (EJDE)[electronic only], 2006)
    In this paper, we study the L2− boundedness and L2− compactness of a class of Fourier integral operators. These operators are bounded (respect ively compact) if the weight of the amplitude is bounded (respectively tends to0).
  • A class of generalized integral operators. 
    Messirdi, Bekkai; Bekkara, Samir; Senoussaoui, Abderrahmane (Electronic Journal of Differential Equations (EJDE)[electronic only], 2009)
    In this paper , we introduce a class of generalized integral operators that includes Fourier integral operators . We establish some conditions on these operators such that they do not have bounded extension on L2(Rn): ...
  • Essential spectra and Drazin invertibility of quasisimilar closed operators 
    Messirdi, Bekkai; Djellouli, Ghouti; Azzouz, Abdelhalim (2018)
    The purpose of this paper is to introduce several generalizations of the notion of similarity between closed operators on a Hilbert space, in particular, the notion of quasi-similarity and mutually quasi-similarity. ...
  • An Example of Unbounded Fourier Integral Operator on L2 with Symbol in 
    Messirdi, Bekkai; Aıboudi, Mohamed; Senoussaoui, Abderrahmane (2007)
    In this paper, we give an example of Fourier integral operator with a symbol belongs to 0<ρ<1 S0 ρ,1 that cannot be extended as a bounded operator on L2 (Rn) .
  • Generalized Kato linear relations 
    Benharrat, Mohammed; Alvarez, Teresa; Messirdi, Bekkai (Filomat, 2017-01-01)
    For a Banach space the notions of generalized Kato linear relation and the corresponding spectrum are introduced and studied. We show that the symmetric di erence between the generalized Kato spectrum and the Goldberg ...
  • Hamiltonians spectrum in Fermi resonance via the Birkhoff–Gustavson normal form 
    Messirdi, Bekkai; Ghomari, Kaoutar (Int. J. Contemp. Math. Sci, 2009)
    We investigate in this paper the theorem of Birkhoff normal form near an equilibrium point in infinite dimension and discuss the dynamical consequences for Schr¨odinger Hamiltonians. We calculate also the spectrum in ...
  • Left and Right Generalized Drazin Invertibility of an Upper Triangular Operator Matrices with Application to Boundary Value Problems 
    Messirdi, Bekkai; Kouider, Miloud Hocine; Benharrat, Mohammed (International Journal of Analysis and Applications, 2019-01-06)
    When A∈ B (H) and B∈ B (K) are given, we denote by MC the operator on the Hilbert space H⊕ K of the form MC=(AC 0 B). In this paper we investigate the quasi-nilpotent part and the analytical core for the upper triangular ...
  • Left and right generalized Drazin invertible operators and Local spectral theory 
    Messirdi, Bekkai; Benharrat, Mohammed; Miloud Hocine, Kouider (arXiv preprint arXiv:1512.02623, 2015-12-08)
    In this paper, we give some characterizations of the left and right generalized Drazin invertible bounded operators in Banach spaces by means of the single-valued extension property (SVEP). In particular, we show that a ...
  • Linear boundary-value problems described by Drazin invertible operators 
    Messirdi, Bekkai; Khaldi, Nassima; Benharrat, Mohammed (Mathematical Notes, 2017-05-01)
    The main subject of this paper is the study of a general linear boundary-value problem with Drazin or right Drazin (respectively, left Drazin) invertible operators corresponding to initial boundary operators. The obtained ...
  • Méthode BKW formelle et spectre des molécules polyatomiques dans l'approximation de Born Oppenheimer 
    Messirdi, Bekkai; Senoussaoui, Abderrahmane (Canadian Journal of Physics, 2001-04-01)
    We studied the spectrum of P D −h21x − 1y C V .x; y/ on L2 􀀀 IR3n x IR3p y ; when h tends to zero; n 2; p 2 IN ; in the case where the potential V .x; y/ is singular and of Coulomb type and the first ...
  • New interpretation of elliptic Boundary value problems via invariant embedding approach and Yosida regularization 
    Messirdi, Bekkai; Bouarroudj, Nadra; Belaib, Lekhmissi (Proyecciones (Antofagasta), 2018-12)
    The method of invariant embedding for the solutions of boundary value problems yields an equivalent formulation to the initial boundary value problems by a system of Riccati operator differential equations. A combined ...
  • On a General Feshbach Method1 
    Messirdi, Bekkai; Benaicha, Slimane; Djaa, Mustapha; Rahmani, Abdelkader (Publié dans International Journal of Mathematical Analysis, Volume1, 2007)
    We present a general reduction Feshbach method that can be applied in particular to the spectral study of operators including the hamiltonian of the Born-Oppenheimer approximation and also to Fredholm operators. This ...
  • On a General Reduction Scheme of Fredholm Operators 
    Messirdi, Bekkai; Djellouli, Ghouti (African Journal Of Mathematical Physics, 2007)
    In this paper we present a new reduction scheme that we can applied to the study of Fredholm operators. We mainly show in a simple and original manner the stability results for Fredholm operators. We also get a fundamental ...
  • On Closed Range Operators in Hilbert Space 
    Messirdi, Bekkai; Ould-Ali, Mohand (International Journal of Algebra, 2010)
    Let C(H) be the set of all linear closed operators densely defined on a Hilbert space H. This paper is devoted to the study of the equivalent statements for which an operator A belongs to C(H) has a closed range.
  • On different concepts of closedness of linear operators 
    Messirdi, Sanaa; Messirdi, Bekkai; Messirdi, Miloud (OaM, Oper. Matrices, 2014-03-01)
    The purpose of this paper is to introduce, by means of the extensions of almost closed operators, the notion of almost closable linear operator acting in a Hilbert or Banach space. This class of operators is strictly ...
  • On Different products of closed operators 
    Messirdi, Bekkai; Mortad, Mohammed Hichem (Banach J. Math. Anal, 2008-01-01)
    The purpose of this work is to give different products of closed operators together with their faults and assets.
  • On the generalized Kato spectrum 
    Benharrat, Mohammed; Messirdi, Bekkai (Serdica Mathematical Journal, 2011)
    We show that the symmetric difference between the generalized Kato spectrum and the essential spectrum defined in [7] by sec(T) = {l О C ; R(lI-T) is not closed } is at most countable and we also give some relationship ...
  • On the Kato, semi-regular and essentially semi-regular spectra 
    Benharrat, Mohammed; Ammar, Aymen; Jeribi, Aref; Messirdi, Bekkai (Functional Analysis, Approximation and Computation, 2015-02-16)
    In this paper, we give some properties of the semi-regular, essentially semi-regular and the operators of Kato type on a Banach space. We also show that the essentially semi-regular spectrum of closed, densely defined ...

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