Kyungpook Mathematical Journal

  • 제63권1호
  • /
  • Pages.1-10
  • /
  • 2023
  • /
  • 1225-6951(pISSN)
  • /
  • 0454-8124(eISSN)
경북대학교 자연과학대학 수학과 (Department of Mathematics, Kyungpook National University)
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Criteria for Algebraic Operators to be Unitary

  • Zenon Jan Jablonski (Instytut Matematyki, Uniwersytet Jagiellonski) ;
  • Jan Stochel (Instytut Matematyki, Uniwersytet Jagiellonski) ;
  • Il Bong Jung (Department of Mathematics, Kyungpook National University)
  • 투고 : 2022.07.05
  • 심사 : 2022.09.19
  • 발행 : 2023.03.31
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초록

Criteria for an algebraic operator T on a complex Hilbert space 𝓗 to be unitary are established. The main one is written in terms of the convergence of sequences of the form {||Tnh||}∞n=0 with h ∈ 𝓗. Related questions are also discussed.

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과제정보

The research of the first and second authors was supported by the National Science Center (NCN) Grant OPUS No. DEC-2021/43/B/ST1/01651. The research of the third author was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2021R111A1A01043569).

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