Correction to: Besse conjecture with positive isotropic curvature

초록

It has been observed that the proof of Lemma 5.5 in the paper [3] is not complete. It was pointed out in [1] by Prof. S. Borghini and L. Mazzieri, and in [2] by Prof. G. Catino, D. Dameno and P. Mastrolia. In the proof, a particular frame of vector fields is constructed in order to establish formulas for |del omega|(2) and |delta omega|(2). The derived formula for delta omega might not be correct as they pointed out because the Lie bracket of these frames does not necessarily vanish.