On polarized 3-folds (X, L) withg(L)=q(X)+1 andh0(L)≥4
Let (X, L) be a polarized 3-fold over the complex number field. In [Fk3], we proved thatg(L)≥q(X) ifh0(L)≥2 and moreover we classified (X, L) withh0(L)≥3 andg(L)=q(X), whereg(L) is the sectional genus of (X, L) andq(X)=dimH1(OX) the irregularity ofX. In this paper we will classify polarized 3-folds (X, L) withh0(L)≥4 andg(L)=q(X)+1 by the method of [Fk3].