It has come to the attention of the IAEA and IOP Publishing that this article substantially duplicates another paper (H Q Liu et al 2007 Operational region and sawteeth oscillation in the EAST tokamak Plasma Phys. Control. Fusion49 995) from the same laboratory. Two versions of the same paper were submitted for publication simultaneously and, consequently, this paper (the later of the two publications) has been retracted. The authors would like to apologise to the community for this unfortunate oversight.