Abstract
For a compact almost complex 4-manifold (M, J ), we study the subgroups H±J of H2 (M,R)consisting of cohomology classes representable by J -invariant, respectively, J -anti-invariant real 2-forms. If b+ = 1, we show that, for generic almost complex structures on M, the subgroup HJ is trivial. Computations of the subgroups and their dimensions h±J are obtained foralmost complex structures related to integrable ones. We also prove semi-continuity propertiesfor h±J.
Original language | English (US) |
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Pages (from-to) | 83-111 |
Number of pages | 29 |
Journal | Quarterly Journal of Mathematics |
Volume | 64 |
Issue number | 1 |
DOIs | |
State | Published - Mar 2013 |
Bibliographical note
Funding Information:During the preparation of this work, the authors benefited from partial support from NSF grant DMS-0604748 (of the second author).