# 4-Manifolds With Inequivalent Symplectic Forms and 3-Manifolds With Inequivalent Fibrations

 Title: 4-Manifolds With Inequivalent Symplectic Forms and 3-Manifolds With Inequivalent Fibrations Author: McMullen, Curtis T.; Taubes, Clifford H. Note: Order does not necessarily reflect citation order of authors. Citation: McMullen, Curtis T., and Cliffor H. Taubes. 1999. 4-Manifolds with inequivalent symplectic forms and 3-manifolds with inequivalent fibrations. Mathematical Research Letters 6(5-6): 681–696. Revised 2003. Full Text & Related Files: McMullen_ManifoldsSymplecticFibration.pdf (256.0Kb; PDF) Abstract: We exhibit a closed, simply connected 4-manifold $$X$$ carrying two symplectic structures whose ﬁrst Chern classes in $$H^2 (X, \mathbb{Z})$$ lie in disjoint orbits of the diffeomorphism group of $$X$$. Consequently, the moduli space of symplectic forms on $$X$$ is disconnected. The example $$X$$ is in turn based on a 3-manifold $$M$$. The symplectic structures on $$X$$ come from a pair of ﬁbrations $$\pi_0, \pi_1 : M \rightarrow S^1$$ whose Euler classes lie in disjoint orbits for the action of $$\mathrm{Diff}(M)$$ on $$H_1(M, \mathbb{R})$$. Published Version: http://www.mrlonline.org/mrl/ Terms of Use: This article is made available under the terms and conditions applicable to Other Posted Material, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#LAA Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:3637160 Downloads of this work: