Let $X$ be a complex space of dimension $n$, not necessarily reduced, whose cohomology groups $H^1(X,𝒪),...,H^{n-1}(X,𝒪)$ are of finite dimension (as complex vector spaces). We show that $X$ is Stein (resp., $1$-convex) if, and only if, $X$ is holomorphically spreadable (resp., $X$ is holomorphically spreadable at infinity). This, on the one hand, generalizes a known characterization of Stein spaces due to Siu, Laufer, and Simha and, on the other hand, it provides a new criterion for $1$-convexity.

Let $E$ be a holomorphic Banach bundle over a compact complex manifold, which can be defined by a cocycle of holomorphic transition functions with values of the form $\mathrm{id}+K$ where $K$ is compact. Assume that the characteristic fiber of $E$ has the compact approximation property. Let $n$ be the complex dimension of $X$ and $0\le q\le n$. Then: If $V\to X$ is a holomorphic vector bundle (of finite rank) with $H^q(X,V)=0$, then $dim{H}^q(X,V\otimes E)\<\infty$. In particular, if $dim{H}^q(X,𝒪)=0$, then $dim{H}^q(X,E)\<\infty$.

Let $X$ be a Banach space with a countable unconditional basis (e.g., $X={\ell }_2$), $\Omega \subset X$ an open set and $f_1,...,f_k$ complex-valued holomorphic functions on $\Omega$, such that the Fréchet differentials $d{f}_1\left(x\right),...,d{f}_k\left(x\right)$ are linearly independant over $ℂ$ at each $x\in \Omega$. We suppose that $M=\{x\in \Omega :f_1\left(x\right)=...=f_k\left(x\right)=0\}$ is a complete intersection and we consider a holomorphic Banach vector bundle $E\to M$. If $I$ (resp.${𝒪}^E$) denote the ideal of germs of holomorphic functions on $\Omega$ that vanish on $M$ (resp. the sheaf of germs of holomorphic sections of $E$), then the sheaf cohomology groups $H^q(\Omega ,I)$, $H^q(M,{𝒪}^E)$ vanish...

A statement in the paper “Holomorphic Morse inequalities on manifolds with boundary” saying that the holomorphic Morse inequalities for an hermitian line bundle $L$ over $X$ are sharp as long as $L$ extends as semi-positive bundle over a Stein-filling is corrected, by adding certain assumptions. A more general situation is also treated.