Extremal Almost-kähler Metrics
نویسنده
چکیده
We generalize the notions of the Futaki invariant and extremal vector field of a compact Kähler manifold to the general almost-Kähler case and show the periodicity of the extremal vector field when the symplectic form represents an integral cohomology class modulo torsion. We also give an explicit formula of the hermitian scalar curvature in Darboux coordinates which allows us to obtain examples of non-integrable extremal almost-Kähler metrics saturating LeBrun’s estimates.
منابع مشابه
On the Kähler Classes of Extremal Metrics
Let (M,J) be a compact complex manifold, and let E ⊂ H1,1(M,R) be the set of all cohomology classes which can be represented by Kähler forms of extremal Kähler metrics, in the sense of Calabi [3]. Then E is an open subset. ∗Supported in part by NSF grant DMS 92-04093. †Supported in part by NSF grant DMS 90-22140.
متن کاملOn Modified Mabuchi Functional and Mabuchi Moduli Space of Kähler Metrics on Toric Bundles
Mabuchi introduced the Mabuchi functional in [Mb1], and it turns out that it is very useful for dealing with Kähler metrics with constant scalar curvatures on compact manifolds (see [BM], etc.). One can also expect that the existence of Kähler metric with constant scalar curvature is almost equivalent to the existence of a lower bound of the Mabuchi functional (see, e.g., [Ti]). But for the cas...
متن کاملPolarized 4-Manifolds, Extremal Kähler Metrics, and Seiberg-Witten Theory
Using Seiberg-Witten theory, it is shown that any Kähler metric of constant negative scalar curvature on a compact 4-manifold M minimizes the L-norm of scalar curvature among Riemannian metrics compatible with a fixed decomposition H(M) = H ⊕ H−. This implies, for example, that any such metric on a minimal ruled surface must be locally symmetric.
متن کاملAsymptotic Properties of Extremal Kähler Metrics of Poincaré Type
Consider a compact Kähler manifold X with a simple normal crossing divisor D, and define Poincaré type metrics on X\D as Kähler metrics on X\D with cusp singularities along D. We prove that the existence of a constant scalar curvature (resp. an extremal) Poincaré type Kähler metric on X\D implies the existence of a constant scalar curvature (resp. an extremal) Kähler metric, possibly of Poincar...
متن کامل