Related papers: withdrawn

This paper has been withdrawn by the author due to its publication

This paper has been withdrawn

This paper is withdrawn.

This submission has been withdrawn by the author.

This paper has been withdrawn by the authors.

This paper has been withdrawn by the author, because it is now part of an enlarged version entitled "Time functions as utilities" arXiv:0909.0890

This paper has been withdrawn by the authors.

This paper has been withdrawn by the author.

This paper has been withdrawn by the author due to errors and bad formalization.

This paper was withdrawn by the authors.

This paper has been withdrawn by author.

This paper has been withdrawn

This paper has been withdrawn.

This paper has been withdrawn by the author, since one of the key results duplicates existing work, as pointed out by a reader. I am currently revising the manuscript.

This paper has been withdrawn by the author due to errors.

This paper has been withdrawn by the author due to a coming paper completely superseding it.

This paper has been withdrawn.

The paper is being withdrawn. A new submission will follow.

This paper has been withdrawn by the author(s),

This paper has been withdrawn.