Compact cohomogeneity one Riemannian manifolds of positive Euler characteristic and quaternionic Kahler manifolds

2012 ◽  
pp. 1-34 ◽  
Author(s):  
D. V. Alekseevsky ◽  
F. Podestà
Keyword(s):  
Euler Characteristic ◽  
Riemannian Manifolds ◽  
Kähler Manifolds ◽  
Kahler Manifolds ◽  
Cohomogeneity One ◽  
Quaternionic Kähler

scholarly journals Curvature of quaternionic Kähler manifolds with $$S^1$$-symmetry

2021 ◽  
Author(s):  
V. Cortés ◽  
A. Saha ◽  
D. Thung
Keyword(s):  
Curvature Tensor ◽  
Decomposition Theorem ◽  
Kähler Manifolds ◽  
Kahler Manifolds ◽  
Riemann Curvature ◽  
Riemann Curvature Tensor ◽  
Cohomogeneity One ◽  
Civita Connection ◽  
Levi Civita Connection ◽  
Quaternionic Kähler

AbstractWe study the behavior of connections and curvature under the HK/QK correspondence, proving simple formulae expressing the Levi-Civita connection and Riemann curvature tensor on the quaternionic Kähler side in terms of the initial hyper-Kähler data. Our curvature formula refines a well-known decomposition theorem due to Alekseevsky. As an application, we compute the norm of the curvature tensor for a series of complete quaternionic Kähler manifolds arising from flat hyper-Kähler manifolds. We use this to deduce that these manifolds are of cohomogeneity one.

scholarly journals QUATERNIONIC KAHLER MANIFOLDS OF COHOMOGENEITY ONE

1999 ◽  
Vol 10 (05) ◽  
pp. 541-570 ◽  
Author(s):  
ANDREW DANCER ◽  
ANDREW SWANN
Keyword(s):  
Simple Group ◽  
Lie Algebras ◽  
Complex Structure ◽  
Kähler Manifolds ◽  
Kahler Manifolds ◽  
Cohomogeneity One ◽  
Cohomogeneity One Action ◽  
Hyperkähler Manifolds ◽  
Adjoint Orbits ◽  
Quaternionic Kähler

Classification results are given for (i) compact quaternionic Kähler manifolds with a cohomogeneity-one action of a semi-simple group, (ii) certain complete hyperKähler manifolds with a cohomogeneity-two action of a semi-simple group preserving each complex structure, (iii) compact 3-Sasakian manifolds which are cohomogeneity one with respect to a group of 3-Sasakian symmetries. Information is also obtained about non-compact quaternionic Kähler manifolds of cohomogeneity one and the cohomogeneity of adjoint orbits in complex semi-simple Lie algebras.

scholarly journals Hyperkähler cones and instantons on quaternionic Kähler manifolds

2020 ◽  
Vol 58 (3) ◽  
pp. 291-323
Author(s):  
Chandrashekar Devchand ◽  
Massimiliano Pontecorvo ◽  
Andrea Spiro
Keyword(s):  
Kähler Manifolds ◽  
Kahler Manifolds ◽  
Quaternionic Kähler

ON HARMONIC AND PSEUDOHARMONIC MAPS FROM PSEUDO-HERMITIAN MANIFOLDS

2017 ◽  
Vol 234 ◽  
pp. 170-210 ◽  
Author(s):  
TIAN CHONG ◽  
YUXIN DONG ◽  
YIBIN REN ◽  
GUILIN YANG
Keyword(s):  
Riemannian Manifolds ◽  
Harmonic Maps ◽  
Kähler Manifolds ◽  
Kahler Manifolds ◽  
Rigidity Results ◽  
Hermitian Manifolds

In this paper, we give some rigidity results for both harmonic and pseudoharmonic maps from pseudo-Hermitian manifolds into Riemannian manifolds or Kähler manifolds. Some foliated results, pluriharmonicity and Siu–Sampson type results are established for both harmonic maps and pseudoharmonic maps.

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