“…Then the problem of estimating the upper bound and lower bound for λ 1 have studied by many authors, including Cheng [4], Lee [9], Li and Wang [12,13], Munteanu [22], Li and Tran [19] and Li and Wang [20], Wang [24], etc... When the Ricci curvature is super Einstein: R i j ≥ −(n + 1)g i j , Munteanu [22] proves that λ 1 ≤ n 2 .…”