A Procedure For Obtaining the Zeros of Functions or their Derivatives by Lagrangean Interpolation

1960 ◽  
Vol 39 (1-4) ◽  
pp. 141-150
Author(s):  
Prescott D. Crout
Keyword(s):  
2009 ◽  
Vol 86 (3) ◽  
pp. 339-354 ◽  
Author(s):  
MINGLIANG FANG ◽  
LAWRENCE ZALCMAN

AbstractLet ℱ be a family of meromorphic functions defined in D, all of whose zeros have multiplicity at least k+1. Let a and b be distinct finite complex numbers, and let k be a positive integer. If, for each pair of functions f and g in ℱ, f(k) and g(k) share the set S={a,b}, then ℱ is normal in D. The condition that the zeros of functions in ℱ have multiplicity at least k+1 cannot be weakened.


2009 ◽  
Vol 86 (1-2) ◽  
pp. 93-106 ◽  
Author(s):  
E. A. Sevast’yanov ◽  
A. A. Dolgoborodov

1959 ◽  
Vol 62 ◽  
pp. 496-501
Author(s):  
L. Kuipers ◽  
P.A.J. Scheelbeek
Keyword(s):  

2005 ◽  
Vol 309 (2) ◽  
pp. 534-543
Author(s):  
Daniel Girela ◽  
M. Auxiliadora Márquez ◽  
José Ángel Peláez

The paper outlines an approach to the calculation of the phase from intensity data based on the properties of the distribution of zeros of functions of exponential type. This leads to a reinterpretation of such phenomena as Gibbs’ or speckle, which underlines their intrinsic unity. The phase problem is solved for functions which present complex zeros by apodization, i.e. by creating a sufficiently large zero-free area. The method is based on a compromise between signal to noise ratio and resolution and is meaningful provided the apodization required is not too severe. Real zeros, for which the phase problem is trivial, occur only for the special case of eigenfunctions of the Fourier transform


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