Reducible hyperplane sections, II.
Beltrametti, M.C. ; Chandler, K.A. ; Sommese, A.J.
Kodai Math. J., Tome 25 (2002) no. 2, p. 139-150 / Harvested from Project Euclid
Let $\hatX$ be a smooth connected subvariety of complex projective space $\pn n$. The question was raised in \cite{CHS} of how to characterize $\hatX$ if it admits a reducible hyperplane section $\hatL$. In the case in which $\hatL$ is the union of $r \geq 2$ smooth normal crossing divisors, each of sectional genus zero, classification theorems were given for $\dim \hatX \geq 5$ or $\dim X=4$ and $r=2$. This paper restricts attention to the case of two divisors on a threefold, whose sum is ample, and which meet transversely in a smooth curve of genus at least $2$. A finiteness theorem and some general results are proven, when the two divisors are in a restricted class including $\pn 1$-bundles over curves of genus less than two and surfaces with nef and big anticanonical bundle. Next, we give results on the case of a projective threefold $\hatX$ with hyperplane section $\hatL$ that is the union of two transverse divisors, each of which is either $\pn 2$, a Hirzebruch surface $\eff_r$, or $\widetilde{\eff_2}$.
Publié le : 2002-06-14
Classification: 
@article{1071674437,
     author = {Beltrametti, M.C. and Chandler, K.A. and Sommese, A.J.},
     title = {Reducible hyperplane sections, II.},
     journal = {Kodai Math. J.},
     volume = {25},
     number = {2},
     year = {2002},
     pages = { 139-150},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1071674437}
}
Beltrametti, M.C.; Chandler, K.A.; Sommese, A.J. Reducible hyperplane sections, II.. Kodai Math. J., Tome 25 (2002) no. 2, pp.  139-150. http://gdmltest.u-ga.fr/item/1071674437/