Characterization of the 4-canonical birationality of algebraic 3-folds, II

Abstract

For nonsingular projective 3-folds $X$ (of general type) whose geometric genus $p_g=h^0(X,K_X)$ is $\ge 5$, the birationality of the fourth canonical map ${\phi }_{4,X}={\Phi }_{|4K_X|}$ was characterized by D.-Q. Zhang and the first author in 2008. This paper aims at characterizing the birationality of ${\phi }_{4,X}$ for those $X$ with $p_g=4$.

arXiv commentRevised version. 20 pages. (to appear) Math. Zeit