A lower bound for (KX+tL)Ln-1 of quasi-polarized manifolds (X,L) with kappa(KX+tL)>= 0

Let (X, L) be a quasi-polarized manifold defined over the complex number fi eld with dim X = n greater than or equal to 2. In this paper, we mainly con sider a lower bound for (K-X + tL)Ln-1 with kappa (K-X + tL) greater than o r equal to 0 and n = 2, 3 for t is an element of Q with 0 less than or equa l to t less than or equal to n - 1. This lower bound is useful to classify (X, L) via the sectional genus g(L). (C) 2001 Academic Press.