Commun. Korean Math. Soc. 1997 Vol. 12, No. 3, 539-541

Dong-Kwan Shin Konkuk University

Abstract : Let $X$ be a smooth projective threefold. Let $C$ be a smooth projective curve and let $f:X\to C$ be a fiber space with connected fiber $S$. Assume that $q_1(S)=0$. Then we have $\displaystyle -\ec \, \es$ $\leq -\ex.$