Curvature Functionals, Optimal Metrics, and the Differential Topology of 4-Manifolds

dc.creatorLeBrun, Claude
dc.date2004-04-13
dc.date.accessioned2026-07-07T05:07:25Z
dc.date.available2026-07-07T05:07:25Z
dc.descriptionThis paper investigates the question of which smooth compact 4-manifolds admit Riemannian metrics that minimize the L2-norm of the curvature tensor. Metrics with this property are called OPTIMAL; Einstein metrics and scalar-flat anti-self-dual metrics provide us with two interesting classes of examples. Using twistor methods, optimal metrics of the second type are constructed on the connected sums kCP_2 for k > 5. However, related constructions also show that large classes of simply connected 4-manifolds do not admit any optimal metrics at all. Interestingly, the difference between existence and non-existence turns out to delicately depend on one's choice of smooth structure; there are smooth 4-manifolds which carry optimal metrics, but which are homeomorphic to infinitely many distinct smooth 4-manifolds on which no optimal metric exists.
dc.descriptionTo appear in "Different Faces of Geometry," Donaldson, Eliashberg, and Gromov, editors; Kluwer/Plenum, 2004
dc.identifierhttps://arxiv.org/abs/math/0404251
dc.identifierhttp://arxiv.org/abs/math/0404251
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/70854
dc.subjectDifferential Geometry
dc.subjectGeometric Topology
dc.subject53C20; 53C28; 57R57
dc.titleCurvature Functionals, Optimal Metrics, and the Differential Topology of 4-Manifolds
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