An upper bound of essential norm of composition operator on H ²(B _n)

Abstract

The authors give an upper bound of the essential norm of a composition operator on H ²(B _n), which involves the counting function in the higher dimensional value distribution theory defined by S. S. Chern. A criterion is also given to assure that the composition operator on H ²( _Bn) is bounded or compact.

Keywords

Essential norm, Composition operator, Hardy space

References

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