scholarly journals Extremals for the Sobolev inequality on the seven dimensional quaternionic Heisenberg group and the quaternionic contact Yamabe problem

2010 ◽  
pp. 1041-1067 ◽  
Author(s):  
Stefan Ivanov ◽  
Ivan Minchev ◽  
Dimiter Vassilev
Keyword(s):  
Heisenberg Group ◽  
Sobolev Inequality ◽  
Yamabe Problem ◽  
Quaternionic Heisenberg Group

Role of the fundamental solution in Hardy—Sobolev-type inequalities

2006 ◽  
Vol 136 (6) ◽  
pp. 1111-1130 ◽  
Author(s):  
Adimurthi ◽  
Anusha Sekar
Keyword(s):  
Fundamental Solution ◽  
Heisenberg Group ◽  
Sobolev Inequality ◽  
Fundamental Solutions ◽  
Sobolev Type ◽  
Best Constant ◽  
Optimal Estimates ◽  
Image Position

Let n ≥ 3, Ω ⊂ Rn be a domain with 0 ∈ Ω, then, for all the Hardy–Sobolev inequality says that and equality holds if and only if u = 0 and ((n − 2)/2)2 is the best constant which is never achieved. In view of this, there is scope for improving this inequality further. In this paper we have investigated this problem by using the fundamental solutions and have obtained the optimal estimates. Furthermore, we have shown that this technique is used to obtain the Hardy–Sobolev type inequalities on manifolds and also on the Heisenberg group.

scholarly journals CONJUGATE POINTS ON THE QUATERNIONIC HEISENBERG GROUP

2003 ◽  
Vol 40 (1) ◽  
pp. 61-72 ◽  
Author(s):  
Chang-Rim Jang ◽  
Jun-Kon Kim ◽  
Yeon-Wook Kim ◽  
Keun Park
Keyword(s):  
Heisenberg Group ◽  
Conjugate Points ◽  
Quaternionic Heisenberg Group

scholarly journals Non-Umbilical Quaternionic Contact Hypersurfaces in Hyper-Kähler Manifolds

2017 ◽  
Vol 2019 (18) ◽  
pp. 5649-5673
Author(s):  
Stefan Ivanov ◽  
Ivan Minchev ◽  
Dimiter Vassilev
Keyword(s):  
Heisenberg Group ◽  
Kähler Manifold ◽  
Kähler Manifolds ◽  
Kahler Manifolds ◽  
Totally Umbilical ◽  
Kahler Manifold ◽  
Compact Case ◽  
Quaternionic Heisenberg Group

Abstract It is shown that any compact quaternionic contact (qc) hypersurfaces in a hyper-Kähler manifold which is not totally umbilical has an induced qc structure, locally qc homothetic to the standard 3-Sasakian sphere. In the non-compact case, it is proved that a seven-dimensional everywhere non-umbilical qc-hypersurface embedded in a hyper-Kähler manifold is qc-conformal to a qc-Einstein structure which is locally qc-equivalent to the 3-Sasakian sphere, the quaternionic Heisenberg group or the hyperboloid.

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