Abstract
This article has been retracted at the request of the Editor-in-Chief and Authors. Please see http://www.elsevier.com/wps/locate/withdrawalpolicy.
Reason: The main subject of our paper, H.M. El-Hawary, E.A. Zanaty and E. El-Sanousy, “Quartic spline collocation methods for elliptic partial differential equations”, AMC, Volume 168, Issue 1 (1 September 2005), 198–221, differs in essential aspects from the Quadratic spline collocation methods used in the published papers:
Christina C. Christara, “Quadratic spline collocation methods for elliptic partial differential equations”, BIT Numerical Mathematics, 34:1, 1994, pp. 33–61;
Ying Zhu, “Quartic-Spline Collocation Methods for Fourth-Order Two-Point Boundary Value Problems”, M.Sc. Thesis, Department of Computer Science, University of Toronto, 2001,73 pages, http://www.cs.toronto.edu/pub/reports/na/ccc/yz-01-msc.ps.gz
and thus reached different results and conclusions. We note, though, that we have followed the formulation and the methods used in these two papers. As citations to this work are also mentioned in our paper, some similarity is apparent in the language of our paper to the other two. But this does not affect the derivation of new and different conclusions.
Nevertheless, we express our apology about this situation and any inconvenience caused to the authors of the above-mentioned papers.
H.M. El-Hawary, E.A. Zanaty and E. El-Sanousy