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Singular hermitian metrics on vector bundles  [PDF]
Mark Andrea A. de Cataldo
Mathematics , 1997,
Abstract: We introduce a notion of singular hermitian metrics (s.h.m.) for holomorphic vector bundles and define positivity in view of $L^2$-estimates. Associated with a suitably positive s.h.m. there is a (coherent) sheaf 0-th kernel of a certain $d''$-complex. We prove a vanishing theorem for the cohomology of this sheaf. All this generalizes to the case of higher rank known results of Nadel for the case of line bundles. We introduce a new semi-positivity notion, $t$-nefness, for vector bundles, establish some of its basic properties and prove that on curves it coincides with ordinary nefness. We particularize the results on s.h.m. to the case of vector bundles of the form $E=F \otimes L$, where $F$ is a $t$-nef vector bundle and $L$ is a positive (in the sense of currents) line bundle. As applications we generalize to the higher rank case 1) Kawamata-Viehweg Vanishing Theorem, 2) the effective results concerning the global generation of jets for the adjoint to powers of ample line bundles, and 3) Matsusaka Big Theorem made effective.
Some adjunction properties of ample vector bundles  [PDF]
Hironobu Ishihara
Mathematics , 1999,
Abstract: Let $E$ be an ample vector bundle of rank $r$ on a projective variety $X$ with only log-terminal singularities. We consider the nefness of adjoint divisors $K_X+(t-r)det(E)$ when $t>=dim(X)$ and $t>r$. As a corollary, we classify pairs $(X,E)$ with $c_r$-sectional genus zero.
Semistability vs. nefness for (Higgs) vector bundles  [PDF]
U. Bruzzo,D. Hernandez Ruiperez
Mathematics , 2003, DOI: 10.1016/j.difgeo.2005.12.007
Abstract: According to Miyaoka, a vector bundle E on a smooth projective curve is semistable if and only if a certain numerical class in the projectivized bundle PE is nef. We establish a similar criterion for the semistability of Higgs bundles: namely, such a bundle is semistable if and only if for every integer s between 0 and the rank of E, a suitable numerical class in the scheme parametrizing the rank s locally-free Higgs quotients of E is nef. We also extend this result to higher-dimensional complex projective varieties by showing that the nefness of the above mentioned classes is equivalent to the semistability of the Higgs bundle E together with the vanishing of the discriminant of E.
Positivity and vanishing theorems for ample vector bundles  [PDF]
Kefeng Liu,Xiaofeng Sun,Xiaokui Yang
Mathematics , 2010,
Abstract: In this paper, we study the Nakano-positivity and dual-Nakano-positivity of certain adjoint vector bundles associated to ample vector bundles. As applications, we get new vanishing theorems about ample vector bundles. For example, we prove that if $E$ is an ample vector bundle over a compact K\"ahler manifold $X$, $S^kE\ts \det E$ is both Nakano-positive and dual-Nakano-positive for any $k\geq 0$. Moreover, $H^{n,q}(X,S^kE\ts \det E)=H^{q,n}(X,S^kE\ts \det E)=0$ for any $q\geq 1$. In particular, if $(E,h)$ is a Griffiths-positive vector bundle, the naturally induced Hermitian vector bundle $(S^kE\ts \det E, S^kh\ts \det h)$ is both Nakano-positive and dual-Nakano-positive for any $k\geq 0$.
Ample vector bundles and branched coverings  [PDF]
Thomas Peternell,Andrew J. Sommese
Mathematics , 1999,
Abstract: Given a covering f: X \to Y of projective manifolds, we consider the vector bundle E on Y given as the dual of f_*(\O_X) / \O_Y. This vector bundles often has positivity properties, e.g. E is ample when Y is projective space by a theorem of Lazarsfeld. In general however E will not be ample due to the geometry of Y. We prove various results when E is spanned, nef or generically nef, under some assumptions on the base Y.
Vanishing theorems for ample vector bundles  [PDF]
Laurent Manivel
Mathematics , 1996, DOI: 10.1007/s002220050126
Abstract: We prove a general vanishing theorem for the cohomology of products of symmetric and skew-symmetric powers of an ample vector bundle on a smooth complex projective variety. Special cases include an extension of classical theorems of Griffiths and Le Potier to the whole Dolbeault cohomology, and an answer to a problem raised by Demailly. An application to degeneracy loci is given.
Rank-2 ample vector bundles on some smooth rational surfaces  [PDF]
Hironobu Ishihara
Mathematics , 1996,
Abstract: Some classification results for ample vector bundles of rank 2 on Hirzebruch surfaces, and on Del Pezzo surfaces, are obtained. In particular, we classify rank-2 ample vector bundles with $c_2$ less than 7 on Hirzebruch surfaces, and with $c_2$ less than 4 on Del Pezzo surfaces.
Stable ample 2-vector bundles on Hirzebruch surfaces  [PDF]
Alexandru Sterian
Mathematics , 2013,
Abstract: We discuss stability conditions for all rank-2 ample vector bundles on Hirzebruch surfaces with the second Chern class less than 7.
Vector bundles on projective varieties whose restriction to ample subvarieties split  [PDF]
Mihai Halic
Mathematics , 2014,
Abstract: We systematically study the splitting of vector bundles on a smooth, projective variety, whose restriction to the zero locus of a regular section of an ample vector bundle splits. First, we find ampleness and genericity conditions which ensure that the splitting of the vector bundle along the subvariety implies its global splitting. Second, we obtain a simple splitting criterion for vector bundles on the Grassmannian and on partial flag varieties.
Effective vanishing theorems for ample and globally generated vector bundles  [PDF]
Kefeng Liu,Xiaokui Yang
Mathematics , 2013,
Abstract: By proving an integral formula of the curvature tensor of $E\ts \det E$, we observe that the curvature tensor of $E\ts \det E$ is very similar to that of a line bundle and obtain certain new Kodaira-Akizuki-Nakano type vanishing theorems for vector bundles. As special cases, we deduce vanishing theorems for ample, nef and globally generated vector bundles by analytic method instead of the Leray-Borel-Le Potier spectral sequence.
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