dist-FORMULAS AND TOEPLITZ OPERATORS

GÜRDAL M. , GARAYEV M. T. , SALTAN S. , YAMANCI U.

ANNALS OF FUNCTIONAL ANALYSIS, cilt.6, ss.221-226, 2015 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 6 Konu: 1
  • Basım Tarihi: 2015
  • Doi Numarası: 10.15352/afa/06-1-16
  • Dergi Adı: ANNALS OF FUNCTIONAL ANALYSIS
  • Sayfa Sayısı: ss.221-226

Özet

The distance from the nonconstant function phi in L-infinity(T) to the set F-const of all constant functions is estimated in terms of Hankel operators on the Hardy space H-2(D) over the unit disk D = {z is an element of C : \z\ < 1}. We give a sufficient condition ensuring the equality dist(phi, F-const) = ||phi||(L infinity). Some other dist-formulas are also discussed.