Related papers: Exchange-Correlation Asymptotics and High Harmonic…

This paper has been withdrawn by the authors due to a likely hole in the proof.

This paper has been withdrawn by the authors. A more complete treatment of the bandstructure effects is forthcoming.

This paper has been withdrawn by the authors.

The paper was withdrawn by the author. It contained various errors.

This paper was withdrawn by the authors.

This paper has been withdrawn, due a wrong analysis of the obtained results.

This paper has been withdrawn due to fundamental errors.

This paper has been withdrawn by the author.

The paper is withdrawn because the analysis appeared to be incomplete.

We withdraw the paper because the results are wrong.

This paper has been withdrawn by the authors, because the authors have second thought that the new ideas in this paper are better to be contained in another paper.

This paper has been withdrawn by the authors.

This paper has been withdrawn by the authors due to an error in the main theorem.

This paper has been withdrawn by the author due to a crucial sign error.

This paper has been withdrawn by the corresponding author because the newest version is now published in Discrete Applied Mathematics.

This paper is withdrawn.

The paper is withdrawn by the author due to an oversimplified and misleading approach which was taken initially as a starting point.

This paper has been withdrawn.

This paper has been withdrawn by the authors due to some technical problems in the paper.

This article has been withdrawn due to an error in a proof of the main result.