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JOURNALS // Matematicheskie Zametki // Archive

Mat. Zametki, 2007 Volume 82, Issue 2, Pages 207–223 (Mi mzm3790)

This article is cited in 1 paper

$U(n+1)\times U(p+1)$-Hermitian Metrics on the Manifold $S^{2n+1}\times S^{2p+1}$

N. A. Daurtseva

Kemerovo State University

Abstract: A two-parameter family of invariant almost-complex structures $J_{a,c}$ is given on the homogeneous space $M\times M'=U(n+1)/U(n)\times U(p+1)/U(p)$; all these structures are integrable. We consider all invariant Riemannian metrics on the homogeneous space $M\times M'$. They depend on five parameters and are Hermitian with respect to some complex structure $J_{a,c}$. In this paper, we calculate the Ricci tensor, scalar curvature, and obtain estimates of the sectional curvature for any metric on $M\times M'$. All the invariant metrics of nonnegative curvature are described. We obtain the extremal values of the scalar curvature functional on the four-parameter family of metrics $g_{a,c,\lambda,\lambda';1}$.

Keywords: Hermitian metric on a homogenous space, Ricci tensor, sectional curvature, Hopf fibration, scalar curvature functional, holomorphic function, Lie algebra, Riemannian connection.

UDC: 514.163

Received: 19.04.2004

DOI: 10.4213/mzm3790


 English version:
Mathematical Notes, 2007, 82:2, 180–195

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