AN OPENNESS THEOREM FOR HARMONIC 2-FORMS ON 4-MANIFOLDS

摘要

Let M be a closed, oriented 4-manifold with b~±_2>0. In this paper we show that the space of transverse intrinsically harmonic 2-forms in a fixed cohomology class is open in the space of closed 2-forms, subject to a condition which arises from cohomological considerations of a singular differential ideal.