Preprints:
A diameter gap for quotients of the unit sphere
(with Claudio Gorodski, Christian Lange, Ricardo Mendes)
Struktur der Submetrien
(Part of the Ph.D. thesis)
Papers Published or Accepted for Publication
Publikationsliste (2020)
Ricci curvature in dimension two
J. Eur. Math. Soc., to appear, (with Stephan Stadler)
Topological regularity of spaces with an upper curvature bound
J. Eur. Math. Soc., to appear, (with Koichi Nagano)
Canonical parametrization of metric discs
Duke Math. J., to appear, (with Stefan Wenger)
Metric measure boundary and geodesic flow on Alexandrov spaces
J. Eur. Math. Soc., to appear, (with Vitali Kapovitch, Anton Petrunin )
Improvements of upper curvature bounds
Trans. Amer. Math. Soc. (with Stephan Stadler)
Dehn functions and Hölder extensions in asymptotic cones
J. Reine Angew. Math., online first (2019) (with Stefan Wenger, Robert Young)
Rigidity of Busemann convex Finsler metrics
Comment. Math. Helv. 94 (2019), 855-868 (with Sergei Ivanov)
Conformal deformation of CAT(0) spaces
Math. Ann. 373 (2019), 155-163 (with Stephan Stadler)
Geodesically complete spaces with an upper curvtaure bound
Geom. Funct. Anal. 29 (2019), 159-202 (with Koichi Nagano )
Intrinisic structure of minimal discs in metric spaces
Geom. Topol. 22 (2018), 591-644 (with Stefan Wenger)
Isoperimetric characterization of upper curvtaure bounds
Acta Math. 221 (2018), 159-202 (with Stefan Wenger )
Algebraic nature of singular Riemannian foliations in spheres
J. Reine Angew. Math. 744 (2018), 265-273 (with Marco Radeschi )
Area minimizing discs in metric spaces
Arch. Rational Mech. Anal. 223 (2017), 1123-1182 (with Stefan Wenger)
Energy and area minimizers in metric spaces
Adv. Calc. Var. 10 (2017), 407-421 (with Stefan Wenger )
The curvature of orbit spaces
Geom. Dedicata 190 (2017), 135-142 (with Claudio Gorodski )
Riemannian foliations of spheres
Geom. Topol. 20 (2016), 1257-1274 (with Burkhard Wilking)
Isometric actions on spheres with an orbifold quotient
Math. Ann. 365 (2016), 1041-1067 (with Claudio Gorodski)
Regularity of harmonic discs in spaces with quadratic isoperimetric inequality
Calc. Var. Partial Differential 55 (2016), 55-98 (with Stefan Wenger)
Riemannian foliations on contractible manifolds
Münster J. Math. 8 (2015), 1-16 (with Luis Florit, Oliver Goertsches, Dirk Töben)
Polar foliations on symmetric spaces
Geom Funct. Anal. 24 (2014) 1298-1315
Homogeneous compact geometries
Transform. Groups 19 (2014) 793-852 (with Linus Kramer)
On orbit spaces of representations of compact Lie groups
J. Reine Angew. Math. 691 (2014), 61-100 (with Claudio Gorodski)
Polar actions on symmetric spaces of higher rank
Bull. London Math. Soc., Vol. 45 (2013), 341-350 (with Andreas Kollross)
On contractible orbifolds
Proc. Amer. Math. Soc., Vol. 141 (2013), 3303-3304
Affine images of Riemannian manifolds
Math. Z., Vol. 270 (2012), 809-817
On smoothness of isometries between orbit spaces
Riemannian geometry and Applications -Proceedings RIGA 2011, 17-28 (with Marcos Alexandrino)
Curvature explosion in quotients and applications
J. Differential Geom. 85 (2010), 117-140 (with Gudlaugur Thorbergsson)
Geometric resolution of singular Riemannian foliations
Geom. Dedicata, Vol. 149 (2010), 379-395
At infinity of finite-dimensional CAT(0) spaces
Math. Ann., Vol. 346 (2010), 1-21 (with Pierre-Emmanuel Caprace)
Notes on the Jacobi equation
Differential Geom. Appl., Vol. 27 (2009), 329-334
Singular Riemannian foliations on spaces without conjugate points
Proceedings of VIII International Colloquium on Differential Geometry (2009), 75-82
The de Rham decomposition theorem for metric spaces
Geom. Funct. Anal., Vol. 18 (2008), 120-143 (with Thomas Foertsch)
Non-positive curvature and the Ptolemy inequality
Int. Math. Res. Not., no. 22 (2007), Art. ID rnm100 (with Thomas Foertsch and Viktor Schroeder)
Affine functions on CAT(k) spaces
Math. Z., Vol. 255 (2007), 231-244 (with Viktor Schroeder)
Spaces with many affine functions
Proc. Amer. Math. Soc., Vol. 135 (2007), 2263-2271 (with P. Hitzelberger)
Variationally complete actions on nonnegatively curved manifolds
Illinois J. Math., Vol. 51 (2007), 605-615 (with G. Thorbergsson)
Tangent spaces and Gromov-Hausdorff limits of subanalytic spaces
J. Reine Angew. Math., Vol. 608 (2007), 1-15 (with Andreas Bernig)
On Hoelder continuous Riemannian and Finsler metrics
Trans. Amer. Math. Soc., Vol. 358 (2006), 2917-2926 (with Asli Yaman)
Building-like spaces
J. Math. Kyoto Univ., Vol. 46 (2006), 789-805 (with Andreas Balser)
Rigidity of spherical buildings and joins
Geom. Funct. Anal., Vol.15 (2005), 720-752
Almost convex subsets
Geom. Dedicata, Vol.115 (2005), 201-218
Centers of convex subsets of buildings
Ann. Global Anal. Geom., Vol.28 (2005), 201-209 (with Andreas Balser)
Open map theorem in metric spaces
Algebra i Analiz, Vol.17 (2005), 139-159
On the geometry of subsets of positive reach
Manuscripta Math. Vol.115 (2004), 199-205
Differentiation in metric spaces
Algebra i Analiz, Vol.16 (2004), 128-161
Metric characterizations of spherical and Euclidean buildings
Geom. Topol., Vol. 5 (2001), 521-550 (with Ruth Charney)