Expected Distances on Manifolds of Partially Oriented Flags

Domains of discontinuity in oriented flag manifolds

We study actions of discrete subgroups $Γ$ of semi-simple Lie groups $G$ on associated oriented flag manifolds. These are quotients $G/P$, where the subgroup $P$ lies between a parabolic subgroup and its identity component. For Anosov subgroups $Γ\subset G$, we identify domains in oriented flag manifolds by removing a set obtained from the limit set of $Γ$, and give a combinatorial description of proper discontinuity and cocompactness of these domains. This generalizes analogous results of Kapovich-Leeb-Porti to the oriented setting. We give first examples of cocompact domains of discontinuity…

Invariant f-structures on the flag manifolds SO(n)/SO(2)xSO(n-3)

We consider manifolds of oriented flags SO(n)/SO(2)xSO(n-3) (n>=4) as 4- and 6-symmetric spaces and indicate characteristic conditions for invariant Riemannian metrics under which the canonical f-structures on these homogeneous $Φ$-spaces belong to the classes Kill f, NKf and G_1f of generalized Hermitian geometry.

Invariant metric $f$-structures on specific homogeneous reductive spaces

For homogeneous reductive spaces G/H with reductive complements decomposable into an orthogonal sum \mathfrak{m}=\mathfrak{m}_1 \oplus \mathfrak{m}_2 \oplus \mathfrak{m}_3 of three Ad(H)-invariant irreducible mutually inequivalent submodules we establish simple conditions under which an invariant metric f-structure (f,g) belongs to the classes G_1 f, NKf, and Kill f of generalized Hermitian geometry. The statements obtained are then illustrated with four examples. Namely we consider invariant metric f-structures on the manifolds of oriented flags SO(n)/SO(2)\times SO(n-3) (n>=4), the Stiefel m…

Prolongation on regular infinitesimal flag manifolds

Many interesting geometric structures can be described as regular infinitesimal flag structures, which occur as the underlying structures of parabolic geometries. Among these structures we have for instance conformal structures, contact structures, certain types of generic distributions and partially integrable almost CR-structures of hypersurface type. The aim of this article is to develop for a large class of (semi-)linear overdetermined systems of partial differential equations on regular infinitesimal flag manifolds $M$ a conceptual method to rewrite these systems as systems of the form $\…

紧埃尔米特局部对称空间上旗丛的上同调

Cohomology of flag bundles over compact Hermitian locally symmetric spaces

本文研究紧埃尔米特局部对称空间上旗丛的上同调，刻画了对应商空间的上同调、Picard群，并推广了单群情形下$p=0,1$时上同调消失的已有结果。

万能向量丛、推前公式和特征形式的正性

Universal vector bundles, push-forward formulae and positivity of characteristic forms

研究万能向量丛的推前公式及特征形式正性，通过计算Chern曲率验证推前公式的点wise成立，并提供微分形式层面的Jacobi-Trudi恒等式替代版本，部分验证Griffiths猜想。