Zobrazeno 1 - 10
of 772
pro vyhledávání: '"Semmelmann A"'
We study the deformability of the symmetric Einstein metrics on the spaces $\mathrm{SU}(n)/\mathrm{SO}(n)$ and $\mathrm{SU}(2n)/\mathrm{Sp}(n)$, thereby concluding the problem to second order for all irreducible symmetric spaces. The obstruction inte
Externí odkaz:
http://arxiv.org/abs/2412.08770
Compact Hermitian symmetric spaces are K\"ahler manifolds with constant scalar curvature and non-negative sectional curvature. A famous result by A. Gray states that, conversely, a compact simply connected K\"ahler manifold with constant scalar curva
Externí odkaz:
http://arxiv.org/abs/2412.00385
Autor:
Artacho, Diego, Semmelmann, Uwe
In this note, we characterise the existence of non-trivial invariant spinors on maximal flag manifolds associated to complex simple Lie algebras. This characterisation is based on the combinatorial properties of their set of positive roots.
Comm
Comm
Externí odkaz:
http://arxiv.org/abs/2407.08493
Autor:
Schwahn, Paul, Semmelmann, Uwe
We study the integrability to second order of the infinitesimal Einstein deformations of the symmetric metric $g$ on the complex Grassmannian of $k$-planes inside $\mathbb{C}^n$. By showing the nonvanishing of Koiso's obstruction polynomial, we chara
Externí odkaz:
http://arxiv.org/abs/2403.04681
The homogeneous minimal hypersurfaces in $S^n$ have $g = 1,2,3,4$, or $6$ distinct (constant) principal curvatures. While the Morse index and nullity have been calculated for all such hypersurfaces having $g = 1,2,3$, it has remained an open problem
Externí odkaz:
http://arxiv.org/abs/2310.19404
In this article we study the concept of quaternionic bisectional curvature introduced by B. Chow and D. Yang for quaternion-K\"ahler manifolds. We show that non-negative quaternionic bisectional curvature is only realized for the quaternionic project
Externí odkaz:
http://arxiv.org/abs/2308.09173
Autor:
Nagy, Paul-Andi, Semmelmann, Uwe
We study the integrability to second order of infinitesimal Einstein deformations on compact Riemannian and in particular on K\"ahler manifolds. We find a new way of expressing the necessary and sufficient condition for integrability to second order,
Externí odkaz:
http://arxiv.org/abs/2305.07391
The aim of this note is to establish the correspondence between the twisted localized Pestov identity on the unit tangent bundle of a Riemannian manifold and the Weitzenb\"ock identity for twisted symmetric tensors on the manifold.
Comment: 22 p
Comment: 22 p
Externí odkaz:
http://arxiv.org/abs/2305.01092
Publikováno v:
Ergod. Th. Dynam. Sys. 44 (2024) 2143-2172
Let $(M,g,J)$ be a closed K\"ahler manifold with negative sectional curvature and complex dimension $m := \dim_{\mathbb{C}} M \geq 2$. In this article, we study the unitary frame flow, that is, the restriction of the frame flow to the principal $\mat
Externí odkaz:
http://arxiv.org/abs/2301.05933
Publikováno v:
IET Smart Grid, Vol 7, Iss 2, Pp 172-185 (2024)
Abstract In modern power systems, predicting the time when peak loads will occur is crucial for improving efficiency and minimising the possibility of network sections becoming overloaded. However, most works in the load forecasting field are not foc
Externí odkaz:
https://doaj.org/article/4289589d31284d05b761bff8df672363
