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Publikacje naukowe

Moje zainteresowania naukowe koncentrują się na zagadnieniach z analizy funkcjonalnej, teorii operatorów liniowych
w przestrzeniach Hilberta oraz analizy nieliniowej. W szczególności interesuję się problemami związanymi z operatorami subnormalnymi, ergodyczną teorią operatorów oraz reprezentacjami spektralnymi operatorów niesamosprzężonych.

Lista publikacji:

  • Krzysztof Bień, Witold Majdak, Nikolaos S. Papageorgiou, Parametric singular problems with an indefinite perturbation, The Journal of Geometric Analysis 34 (2024), Article no. 103.
  • Michał Bełdziński, Marek Galewski, Witold Majdak, On the nonlinear perturbations of self-adjoint operators, Advances in Nonlinear Analysis 11 (2022), 1117–1133.
  • Witold Majdak, Laurian Suciu, Convex and expansive liftings close to two-isometries and power bounded operators, Linear Algebra and its Applications 617 (2021), 1-26.
  • Witold Majdak, Laurian Suciu, Triangulations of operators with two-isometric liftings, Integral Equations Operator Theory 93 (2021), no. 1, 10.
  • Witold Majdak, Laurian Suciu, Brownian type parts of operators in Hilbert spaces, Results Math (2020) 75:5.
  • Witold Majdak, Laurian Suciu, Brownian isometric parts of concave operators, New York J. Math. 25 (2019), 1067–1090.
  • Witold Majdak, Mostafa Mbekhta, Laurian Suciu, Operators intertwining with isometries and Brownian parts of 2-isometries, Linear Algebra and its Applications 509 (2016), 168–190.
  • Witold Majdak, Jerzy B. Stochel, Weighted shifts on directed semi-trees: an application to creation operators on Segal-Bargmann spaces, Complex Anal. Oper. Theory 10 (2016), 1427–1452.
  • Ewelina Zalot, Witold Majdak, Spectral representations for a class of banded Jacobi-type matrices, Opuscula Math. 34 (2014), 871-887.
  • Witold Majdak, Nicolae-Adrian Secelean, Laurian Suciu, Ergodic properties of operators in some semi-Hilbertian spaces, Linear and Multilinear Algebra 61 (2013), 139–159.
  • Majdak, Jan Stochel, A local lifting theorem for jointly subnormal families of unbounded operators, Integral Equations Oper. Theory 69 (2011), 233-246.
  • Witold Majdak, A lifting theorem for unbounded quasinormal operators, J. Math. Anal. Appl. 332 (2007), 934-946.
  • Witold Majdak, Zoltan Sebestyen, Jan Stochel, James E. Thomson, A local lifting theorem for subnormal operators, Proc. Amer. Math. Soc. 134 (2006), 1687-1699.

Promotor pomocniczy doktoratu:

    Michał Bełdziński, Monotonicity and variational methods in Banach spaces with applications in differential equations driven by nonlinear operators, Instytut Matematyki, Politechnika Łódzka 2023.