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Scientific activity

My research interests focus on topics from functional analysis, the theory of linear operators in Hilbert spaces (in particular, subnormal operators, ergodic operator theory and spectral representations of nonselfadjoint operators), and some problems from the field of nonlinear analysis.

List of publications:

ORCID ID: 0000-0002-1952-0706

  • 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.

Recent visits / participation in conferences:

  • Conference "IWOTA 2022", Kraków, Poland, September 6-10, 2022.
  • Conference "Operator Theory and Beyond 2022", Jagiellonian University, Kraków, Poland, June 29 - July 1, 2022.
  • Visiting Senior Scholar at Heilongjiang Institute of Technology, Harbin, China, December 2-21, 2018; talks at:
    • Harbin Engineering University, Harbin, China, December 5,
    • Harbin Institute of Technology, Harbin, China, December 6,
    • Heilongjiang Institute of Technology, Harbin, China, December 7,
    • Workshop on Nonlinear Analysis and Applications, Central South University, Changsha, China, December 9-11 (two reports),
    • Chinese Academy of Sciences, Beijing, China, December 13,
    • 3rd International Workshop on Nonlinear Analysis and its Applications, Heilongjiang Institute of Technology, Harbin, China, December 15-17,
    • Chongqing Technology and Business University, Chongqing, China, December 18,
  • Conference "Recent Advances in Nonlinear Analysis", Levico Terme (Trento), Italy, May 28-30, 2018.

Editorial activity:

  • Managing Editor of the journal Opuscula Mathematica

Conference organizational activity:

  • Member of the Organizing Committee of the conference "IWOTA 2022", Kraków, Poland (September 6-10, 2022).
  • Co-organizer of "Elsevier - JMAA Conference on Nonlinear Analysis at AGH UST" (October 11-12, 2019)
  • Member of the Organizing Committee of the Jubilee Congress of Polish Mathematicians for the 100th Anniversary of the Polish Mathematical Society (September 3-7, 2019)
  • Organizational support for the conference "Dynamics, Equations and Applications" (September 16-20, 2019)
  • Organizational support for the conference "On the Trail of Women in Mathematics" (September 31 - October 2, 2019)
  • Member of the Organizing Committee of the conference "100 Years of Forensics" (July 7, 2019)
  • Member of the Organizing Committee of the conference "Forensics - Science, Modern Technologies" (September 20–22, 2017)
  • Co-organizer of the conference "Spectral Theory and Applications (STA 2017)"
  • Co-organizer of the conference "Spectral Theory and Applications (STA 2015)"
  • Program coordinator of the 6th European Congress of Mathematicians (2012)
  • Member of the Organizing Committee of the conference "Functions and Operators" (2010)