English

Cohomologies on almost complex manifolds and the $\partial \bar{\partial}$-lemma

Differential Geometry 2022-11-02 v4

Abstract

We study cohomologies on an almost complex manifold (M,J)(M, J), defined using the Nijenhuis-Lie derivations LJ\mathcal{L}_J and LN\mathcal{L}_N induced from the almost complex structure JJ and its Nijenhuis tensor NN, regarded as vector-valued forms on MM. We show how one of these, the NN-cohomology HN(M)H^{\bullet}_N (M), can be used to distinguish non-isomorphic non-integrable almost complex structures on MM. Another one, the JJ-cohomology HJ(M)H^{\bullet}_J (M), is familiar in the integrable case but we extend its definition and applicability to the case of non-integrable almost complex structures. The JJ-cohomology encodes whether a complex manifold satisfies the ˉ\partial \bar{\partial}-lemma, and more generally in the non-integrable case the JJ-cohomology encodes whether (M,J)(M, J) satisfies the dLJ\mathrm{d} \mathcal{L}_J-lemma, which we introduce and motivate in this paper. We discuss several explicit examples in detail, including a non-integrable example. We also show that HJkH^k_J is finite-dimensional for compact integrable (M,J)(M, J), and use spectral sequences to establish partial results on the finite-dimensionality of HJkH^k_J in the compact non-integrable case.

Keywords

Cite

@article{arxiv.1710.04695,
  title  = {Cohomologies on almost complex manifolds and the $\partial \bar{\partial}$-lemma},
  author = {Ki Fung Chan and Spiro Karigiannis and Chi Cheuk Tsang},
  journal= {arXiv preprint arXiv:1710.04695},
  year   = {2022}
}

Comments

23 pages. Version 4: Changes made after publication: We corrected a misstatement in Theorem 3.23 and improved the original notation of Theorem 3.32 which caused unnecessary confusion. The authors thank Scott Wilson for alerting us to these issues

R2 v1 2026-06-22T22:12:03.168Z