The Frölicher spectral sequence can be arbitrarily non degenerate
arXiv:0709.0481
Abstract
The Frölicher spectral sequence of a compact complex manifold measures the difference between Dolbeault cohomology and de Rham cohomology. We construct for nilmanifolds with left-invariant complex structure such that the -th differential does not vanish. This replaces an earlier incorrect example by the second author.
5 pages, Lemma 2 in v2 incorrect. v3: First author added, new example constructed (by the same method). Shorter Erratum will appear in Math. Ann. as well