Finiteness of totally geodesic exceptional divisors in Hermitian locally symmetric spaces

2018 ◽  
Vol 146 (4) ◽  
pp. 613-631
Author(s):  
Vincent KOZIARZ ◽  
Julien MAUBON
Keyword(s):  
Symmetric Spaces ◽  
Locally Symmetric Spaces ◽  
Totally Geodesic

scholarly journals Brauer equivalent number fields and the geometry of quaternionic Shimura varieties

2018 ◽  
Vol 70 (2) ◽  
pp. 675-687
Author(s):  
Benjamin Linowitz
Keyword(s):  
Symmetric Spaces ◽  
Number Fields ◽  
Shimura Varieties ◽  
Brauer Groups ◽  
Locally Symmetric Spaces ◽  
Totally Geodesic ◽  
Equivalent Number ◽  
Geodesic Surfaces

Abstract Two number fields are said to be Brauer equivalent if there is an isomorphism between their Brauer groups that commutes with restriction. In this paper, we prove a variety of number theoretic results about Brauer equivalent number fields (for example, they must have the same signature). These results are then applied to the geometry of certain arithmetic locally symmetric spaces. As an example, we construct incommensurable arithmetic locally symmetric spaces containing exactly the same set of proper immersed totally geodesic surfaces.

On the cohomology of uniform arithmetically defined subgroups in SU*(2n)

2011 ◽  
Vol 151 (3) ◽  
pp. 421-440 ◽  
Author(s):  
JOACHIM SCHWERMER ◽  
CHRISTOPH WALDNER
Keyword(s):  
Lie Group ◽  
Symmetric Spaces ◽  
Automorphic Forms ◽  
Close Relation ◽  
Unitary Representations ◽  
Geometric Constructions ◽  
Locally Symmetric Spaces ◽  
Totally Geodesic ◽  
Irreducible Unitary Representations

AbstractWe study the cohomology of compact locally symmetric spaces attached to arithmetically defined subgroups of the real Lie group G = SU*(2n). Our focus is on constructing totally geodesic cycles which originate with reductive subgroups in G. We prove that these cycles, also called geometric cycles, are non-bounding. Thus this geometric construction yields non-vanishing (co)homology classes.In view of the interpretation of these cohomology groups in terms of automorphic forms, the existence of non-vanishing geometric cycles implies the existence of certain automorphic forms. In the case at hand, we substantiate this close relation between geometry and automorphic theory by discussing the classification of irreducible unitary representations of G with non-zero cohomology in some detail. This permits a comparison between geometric constructions and automorphic forms.

scholarly journals THE STRUCTURE OF HARMONIC MORPHISMS WITH TOTALLY GEODESIC FIBRES

2004 ◽  
Vol 06 (03) ◽  
pp. 419-430 ◽  
Author(s):  
M. T. MUSTAFA
Keyword(s):  
Riemannian Manifolds ◽  
Symmetric Spaces ◽  
Positive Curvature ◽  
Compact Manifolds ◽  
Harmonic Morphisms ◽  
Compact Type ◽  
Riemannian Submersions ◽  
Locally Symmetric Spaces ◽  
Totally Geodesic ◽  
Negatively Curved

The structure of local and global harmonic morphisms between Riemannian manifolds, with totally fibres, is investigated. It is shown that non-positive curvature of the domain obstructs the existence of global harmonic morphisms with totally geodesic fibres and the only such maps from compact Riemannian manifolds of non-positive curvature are, up to a homothety, totally geodesic Riemannian submersions. Similar results are obtained for local harmonic morphisms with totally geodesic fibres from open subsets of non-negatively curved compact and non-compact manifolds. During the course, we prove non-existence of submersive harmonic morphisms with totally geodesic fibres from some important domains, for instance from compact locally symmetric spaces of non-compact type and open subsets of symmetric spaces of compact type.

Sign in / Sign up

Export Citation Format

Share Document