Abstract
Let $f \colon X \to Y$ be a fibration from a smooth projective $3$-fold to a smooth projective curve, over an algebraically closed field $k$ of characteristic $p \gt 5$. We prove that if the generic fiber $X_{\eta}$ has big canonical divisor $K_{X_{\eta}}$, then\[ \kappa(X) \geq \kappa(Y) + \kappa(X_{\eta}).\]
Citation
Lei Zhang. "A Note on Iitaka's Conjecture $C_{3,1}$ in Positive Characteristics." Taiwanese J. Math. 21 (3) 689 - 704, 2017. https://doi.org/10.11650/tjm/7931
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