Let $(M,J)$ be a smooth almost complex manifold. There exists a complex manifold structure on $M$ inducing the given almost complex structure $J$ if and only if the Nijenhuis tensor satisfies
\begin{align*}
N_J=0.
\end{align*}
Knowledge Status
Geometry
Discussion
Let be a smooth almost complex manifold.. It records a reusable fact about complex manifolds, Hermitian metrics, holomorphic bundles, or Chern-theoretic invariants.