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If $(E,h)$ is a holomorphic vector bundle over a compact complex manifold $M$ (which is a projective variety), and $S$ is a coherent subsheaf of $M$, then $S$ is secretly a holomorphic vector bundle outside a codimension $2$ subvariety $Y$. On $X-Y$, the vector bundle $S$ inherits the Chern connection from $(E,h)$. So we can form Chern-Weil forms $c_k$ on $X-Y$.

1) Are the forms $c_k \wedge \alpha_{n-k}$ (where $\alpha_{n-k}$ is a smooth $(n-k,n-k)$ closed form on $X$) integrable on $X-Y$ ?

2) If so, if we integrate $c_k \wedge \alpha_{n-k}$ (where $\alpha_{n-k}$ is a smooth $(n-k,n-k)$ closed form on $X$) over $X-Y$, then do we get $[c_k(S)].[\alpha_{n-k}]$ ? (where the Chern classes of coherent sheaves are defined using a free resolution and the cup product formula)

If so, can you please point me to a reference ?

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  • $\begingroup$ In general, there is no global locally free resolution in the complex analytic setting. The definition of the classes $c_k(S)$ are more subtle. $\endgroup$
    – abx
    Commented Feb 1, 2018 at 9:48
  • $\begingroup$ Even for smooth projective varieties ? $\endgroup$
    – Vamsi
    Commented Feb 1, 2018 at 9:52
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    $\begingroup$ No, for projective (or even quasi-projective) varieties there is no problem. As I said, the problem is in the complex analytic setting. $\endgroup$
    – abx
    Commented Feb 1, 2018 at 10:13
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    $\begingroup$ the more subtle definition in the complex analytic setting was obtained here jstor.org/stable/2374215 $\endgroup$
    – YangMills
    Commented Feb 1, 2018 at 18:31

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