Related papers: Variance Reduction Methods for Sublinear Reinforce…

This paper has been withdrawn by the authors, because of serious experimental problems.

This paper has been withdrawn.

The methods used to prove the main result must be incorrect, as they can be used to arrive at a contradiction with previously known results. Thus the paper was withdrawn.

This paper has been withdrawn by the author due to the gaps in the proofs of Proposition 2.2 and Proposition 3.2

This paper has been withdrawn by the authors due to need of essential revision.

The paper has been withdrawn due to a crucial error in section 3.

This paper has been withdrawn by the author due to a crucial error.

This paper has been withdrawn by the author: it was a too preliminary version

The paper is withdrawn due to mistakes in the proofs for Proposition 1.2 and Theorem 2.2.

This paper has been withdrawn by the author due to text overlap with arXiv:1102.5004, as well as omission of proper citations to arXiv:1110.4655 and arXiv:1111.0313

This paper was withdrawn by the authors.

The paper was withdrawn because of its significant overlap with a paper appeared recently.

This paper has been withdrawn by the author.

This paper has been withdrawn at the author's request.

This paper has been withdrawn.

The paper has been withdrawn by the author.

This paper has been withdrawn by the author due to a serious mistake on Lemma 2.4.

This paper has been withdrawn by the authors. We have discovered an error in the evaluation of the diagram, which invalidates our conclusion.

Due to a computational mistake this paper has been withdrawn.

This paper has been withdrawn by the author due to an error estimate in Lemma 3.1.