43 citations · 54 across the 10 of their papers we have counts for
10 papers
Deformations of nearly parallel G_2-structures
Bogdan Alexandrov, Uwe Semmelmann
We study the infinitesimal deformations of a proper nearly parallel G_2-structure and prove that they are characterized by a certain first order differential equation. In particula…
The first eigenvalue of the Dirac operator on locally reducible Riemannian manifolds
Bogdan Alexandrov
We prove a lower estimate for the first eigenvalue of the Dirac operator on a compact locally reducible Riemannian spin manifold with positive scalar curvature. We determine also t…
Almost Hermitian 6-Manifolds Revisited
Bogdan Alexandrov, Thomas Friedrich, Nils Schoemann
A Theorem of Kirichenko states that the torsion 3-form of the characteristic connection of a nearly Kähler manifold is parallel. On the other side, any almost hermitian manifold of…
Hermitian spin surfaces with small eigenvalues of the Dolbeault operator
Bogdan Alexandrov
We study the compact Hermitian spin surfaces with positive conformal scalar curvature on which the first eigenvalue of the Dolbeault operator of the spin structure is the smallest…
On weak holonomy
Bogdan Alexandrov
We prove that SU(n) (n > 2) and Sp(n)U(1) (n > 1) are the only connected Lie groups acting transitively and effectively on some sphere which can be weak holonomy groups of a Rieman…
Sp(n)U(1)-connections with parallel totally skew-symmetric torsion
Bogdan Alexandrov
We consider the unique Hermitian connection with totally skew-symmetric torsion on a Hermitian manifold. We prove that if the torsion is parallel and the holonomy is Sp(n)U(1), con…