대한수학회보 (Bulletin of the Korean Mathematical Society)

  • 제37권2호
  • /
  • Pages.347-352
  • /
  • 2000
  • /
  • 1015-8634(pISSN)
  • /
  • 2234-3016(eISSN)
대한수학회 (Korean Mathematical Society)
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A PROPAGATION OF QUADRATICALLY HYPONORMAL WEIGHTED SHIFTS

  • 발행 : 2000.05.01
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초록

In this note we answer to a question of Curto: Non-first two equal weights in the weighted shift force subnormality in the presence of quadratic hyponormality. Also it is shown that every hyponormal weighted shift with two equal weights cannot be polynomially hyponormal without being flat.

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참고문헌

  1. Proc. Amer. Math. Soc. v.103 On hyponormality of operators A. Athavale
  2. Duke Math. J. v.22 Subnormal operators J. Bram
  3. Research Notes in Mathematics v.51 Subnormal Operators J.B. Conway
  4. Int. Eq. Op. Th v.13 Quadratically hyponormal weighted shifts R.E. Curto
  5. Int. Eq. Op. Th v.18 Recursively generated weighted shifts and the subnormal completion problem R.E. Curto;L.A. Fialkow
  6. Operator Th: Adv. Appl. v.35 Hyponormal pairs of commuting operators R.E. Curto;P. Muhly;J. Xia
  7. Pacific J. Math. v.17 Which weighted shift are subnormal J. Stampfli