scholarly journals Monotonicity of the error term in Gauss-Turán quadratures for analytic function

2007 ◽  
Vol 48 (4) ◽  
pp. 567-581 ◽  
Author(s):  
Gradimir V. Milovanović ◽  
Miodrag M. Spalević

AbstractFor Gauss–Turán quadrature formulae with an even weight function on the interval [−1, 1] and functions analytic in regions of the complex plane which contain in their interiors a circle of radius greater than I, the error term is investigated. In some particular cases we prove that the error decreases monotonically to zero. Also, for certain more general cases, we illustrate how to check numerically if this property holds. Some ℓ2-error estimates are considered.

1981 ◽  
Vol 33 (5) ◽  
pp. 1255-1260 ◽  
Author(s):  
Thomas A. Metzger

Let Δ denote the unit disk in the complex plane C. The space BMO has been extensively studied by many authors (see [3] for a good exposition of this topic). Recently, the subspace BMOA (Δ) has become a topic of interest. An analytic function f, in the Hardy class H2(A), belongs to BMOA (Δ) if(1)whereIt is known (see [3, p. 96]) that (1) is equivalent to(2)


1977 ◽  
Vol 29 (4) ◽  
pp. 701-706 ◽  
Author(s):  
P. M. Gauthier ◽  
W. Hengartner

Let ƒ be a complex-valued function denned on a closed subset F of the finite complex plane C, and let {Zn} be a sequence on F without limit points. We wish to find an analytic function g which simultaneously approximates ƒ uniformly on F and interpolates ƒ at the points {Zn}.


1987 ◽  
Vol 27 (1) ◽  
pp. 85-97 ◽  
Author(s):  
Ulf Torsten Ehrenmark

Author(s):  
Songxiao Li

We study the following integral operators:Jgf(z)=∫0zf(ξ)g′(ξ)dξ;Igf(z)=∫0zf′(ξ)g(ξ)dξ, wheregis an analytic function on the open unit disk in the complex plane. The boundedness and compactness ofJg,Igbetween the Bergman-type spaces and theα-Bloch spaces are investigated.


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