Uwe Semmelmann

Preprints:

• The Morse index of quartic minimal hypersurfaces
  (with Gavin Ball, Jesse Madnick)
  [arXiv:2310.19404]
  
  
• On the ergodicity of the frame flow on even-dimensional manifolds
  (with Mihajlo Cekić, Thibault Lefeuvre, Andrei Moroianu)
  [arXiv:2111.14811]
  
  
• On quaternionic bisectional curvature
  (with Oscar Macia, Gregor Weingart)
  [arxiv.org/abs/2308.09173]
  
  
• Second order Einstein deformations
  (mit Paul-Andi Nagy)
  [arxiv.org/abs/2305.07391]
  
  
• Correspondence between Pestov and Weitzenböck identities
  (with Mihajlo Cekić, Thibault Lefeuvre, Andrei Moroianu)
  [arxiv.org/abs/2305.01092]
  
  
  

Publikationen:

Liste im: [arXiv] bzw im: [MSciN]

1. The G_2 geometry of 3-Sasaki structures
   to appear in:  J. Geom. Anal. [arXiv:2101.04494]
   (mit Paul-Andi Nagy)
2. On the ergodicity of unitary frame flows on Kähler manifolds
   to appear in:  Ergod. Theory Dyn. Syst. [arXiv:2301.05933]
   (with Mihajlo Cekić, Thibault Lefeuvre, Andrei Moroianu)
3. Eigenvalue estimates for 3-Sasaki structures
   J. Reine Angew. Math. 803 (2023), 35–60. [arXiv:2107.12982]
   (mit Paul-Andi Nagy)
4. Stability of the Non-Symmetric Space E7/PSO(8)
   Adv. Math. 432 (2023), Paper No. 109268, 23 pp. [arXiv:2203.10138]
   (mit Paul Schwahn und Gregor Weingart)
5. Conformal Killing forms in Kähler geometry
   Illinois J. Math. 66 (2022), no. 3, 349–384. [arXiv:2003.09184]
   (with Paul-Andi Nagy)
6. Towards Brin's conjecture on frame flow ergodicity: new progress and perspectives
   Math. Res. Rep. 3 (2022), 21–34. [arXiv:2204.08728]
   (with Mihajlo Cekić, Thibault Lefeuvre und Andrei Moroianu).
7. Linear Instability of Sasaki Einstein and nearly parallel G2 manifolds
   J. Geom. Anal. 33 (2022), no. 6, Paper No. 2250042, 17 pp. [arXiv:2011.11965]
   (with Changliang Wang und McKenzie Wang)
8. Stability of Compact Symmetric Spaces,
   The Journal of Geometric Analysis 32 (2022) 32:137 [arXiv:2012.07328]
   (with Gregor Weingart)
9.  Deformations of nearly G2-structures,
   J. London Math. Soc. (2) 104 (2021) 1795–1811 [arXiv:2007.01657]
   (with Paul-Andi Nagy)
10. Metric connections with parallel skew-symmetric torsion,
    Adv. Math. 378, 107519 (2021) [arXiv:1807.00191]
    (with Richard Cleyton, Andrei Moroianu)
11. An Obata-type characterization of doubly-warped product Kähler manifolds,
    Münster J. Math. 14 (2021), no. 2, 295-321 [arXiv:2002.08808]
    (with Nicolas Ginoux, Georges Habib, Mihaela Pilca)
12. An Obata-type characterization of Calabi metrics on line bundles,
    North-West. Eur. J. Math. 6 (2020), 119-136 [arXiv:2002.08810]
    (with Nicolas Ginoux, Georges Habib, Mihaela Pilca)
13. Conformal Killing forms on nearly Kähler manifolds,
    Differential Geom. Appl. 70 (2020), [arXiv:1903.06734]
    (with Antonio M. Naveira)
14. On the linear stability of nearly Kähler 6-manifolds,
    Ann. Global Anal. Geom. 57 no. 1, 15-22 (2020), [arXiv:1907.12512]
    (with C. Wang and M. Wang).
15. Generalized vector cross products and Killing forms on negatively curved manifolds,
    Geom. Dedicata 205 (1), 113-127 (2020), [arXiv:1806.06255]
    (with Laura Barberis and Andrej Moroianu)
16. The kernel of the Rarita-Schwinger operator on Riemannian spin manifolds,
    Comm. Math. Phys. 370 no. 3, 853-871 (2019), [arXiv:1804.10602]
    (with Yasushi Homma)
17. The Standard Laplace operator
    Manuscripta Math. 158, no. 1-2, 273-293 -8273-293, [arXiv:1708.04775]
    (with G. Weingart)
18. Killing tensors on tori
    J. Geo. Phys. 117, 1-6 (2017), [arXiv:1610.02009]
    (with Konstantin Heil und Andrei Moroianu)
    
19. Killing and Conformal Killing tensors
    J. Geom. Phys. 106, 383-400 (2016), [pdf]
    (with Konstantin Heil und Andrei Moroianu)
20. Generalized Killing spinors and Lagrangian graphs
    Differ. Geom. Appl. 37 (2014), 141-151, [arXiv:1405.0838], [pdf]
    (with Andrei Moroianu)
21. Generalized Killing spinors on Spheres
    Ann. Global Anal. Geom. 46 (2014), no. 2, 129-143, [arXiv:1310.0219], [pdf]
    (with Andrei Moroianu)
22. Weakly complex homogeneous spaces
    J. reine angew. Math. 691 (2014), 229-244, [arXiv:1202.3363], [pdf]
    (with Andrei Moroianu)
23. Generalized Killing spinors on Einstein manifolds
    Internat. J. Math. 25 (2014), no. 4, 1 - 19, [arXiv:1303.6179], [pdf]
    (with Andrei Moroianu)
24. Homogeneous almost quaternion-Hermitian manifolds
    Math. Ann. 357 (2013), no. 4, 1205-121, [arXiv:1211.4383], [pdf]
    (with Andrei Moroianu und Mihaela Pilca)
25. Invariant four-forms and symmetric pairs
    Ann. Global. Anal. Geom. 43, 107-121 (2013), [arXiv:1202.3407], [pdf]
    (with Andrei Moroianu)
26. Extrinsic hyperspheres in manifolds with special holonomy
    Differ. Geom. Appl. 31, 104-111 (2013], [arXiv:1107.1603], [pdf]
    (with Andrei Moroianu und Tillmann Jentsch)
27. Deformations of nearly parallel G_2-structures
    Asian Journal of Math. Vol. 16, No. 4, 713-744 (2012), [arXiv:1101.2143 ], [pdf]
    (with Bogdan Alexandrov)
28. Imaginary Kählerian Killing spinors I
    Ann. Global Anal. Geom. 40, no. 4, 467--495 (2011), [arXiv:1102.4263], [pdf]
    (with Nicolas Ginoux)
29. Clifford structures on Riemannian manifolds
    Adv. Math. 228, 940-967 (2011), [arXiv:0912.4207], [pdf]
    (with Andrei Moroianu)
30. Almost complex structures on quaternion-Kähler manifolds and inner symmetric spaces,
    Invent. Math. 184, 389-403 (2011), [arXiv:1003.5172], [pdf]
    (with Andrei Moroianu und Paul Gauduchon)
31. Infinitesimal Einstein deformations of nearly Kähler metrics,
    Trans. Amer. Math. Soc. 363, 3057-3069 (2011), [arXiv:0702455], [pdf]
    (with Andrei Moroianu)
32. The Hermitian Laplace operator on nearly Kähler manifolds
    Commun. Math. Phys. 294, 251-272 (2010), [arXiv:0810.0164], [pdf]
    (with Andrei Moroianu)
33. The Weitzenböck machine
    Compositio Math. 146, 2, 507-540 (2010), [arXiv:0702031], [pdf]
    (with Gregor Weingart)
34. Deformations of nearly Kähler structures
    Pacific J. Math. 235, 57-72 (2008), [arXiv:0611223], [pdf]
    (with Andrei Moroianu und Paul-Andi Nagy)
35. Killing forms on G2 and Spin7 manifolds
    J. Geom. Phys. 56 (2006) 1752-1766, [arXiv:0410065 ], [pdf].
36. Killing forms on quaternion-Kähler manifolds
    Ann. Global Anal. Geom. 28, 319-335 (2005],
    erratum 34, 431-432 (2008), [arXiv:0403242], [pdf1], [pdf2]
    (with Andrei Moroianu)
37. Killing forms on symmetric spaces
    Differential Geom. Appl. 24, 215-222 (2006), [arXiv:0409104], [pdf]
    (with Florin Belgun und Andrei Moroianu)
38. Twistor forms on Riemannian products
    J. Geom. Phys. 58, 1343-1345 (2008), [arXiv:0407063], [pdf]
    (with Andrei Moroianu)
39. Unit Killing vector fields on nearly Kähler manifolds
    Internat. J. Math. 16, 281-301 (2005), [arXiv:0406492], [pdf]
    (with Andrei Moroianu und Paul-Andi Nagy)
40. An upper bound for a Hilbert polynomial on quaternionic Kähler manifolds
    J. Geom. Anal. 14 (2004), 151--170, [arXiv:0208079], [pdf]
    (with Gregor Weingart)
41. Conformal Killing forms on Riemannian Manifolds
    Math. Z. 245 (2003), no. 3, 503--527, [arXiv:0206117], [pdf],
    Habilitationsschrift: pdf
42. Twistor forms on Kähler manifolds
    Ann. Sc. Norm. Super. Pisa Cl. Sci. 2, 823-845 (2003), [arXiv:0204322], [pdf]
    (with Andrei Moroianu)
43. Symmetries of contact metric manifolds
    Geometriae Dedicata 101, 203-216 (2003), [arXiv:0203090], [pdf]
    (with Florin Belgun und Andrei Moroianu)
44. Scalar Curvature Estimates for Compact Symmetric Spaces
    Differential Geom. Appl. 16 (2002), no. 1, 65-78, [arXiv:/0010199], [pdf]
    (with Sebastian Goette)
45. Vanishing Theorems for Quaternionic Kähler Manifolds
    J. Reine Angew. Math. 544 (2002), 111-132, [arXiv:/0001061], [pdf]
    (with Gregor Weingart)
46. Spin^c Structures and Scalar Curvature Estimates
    Ann. Glob. Anal. Geom. , 20 (4):301-324 (2001), [arXiv:/9905089], [pdf]
    (with Sebastian Goette)
47. The point spectrum of the Dirac operator on noncompact symmetric spaces
    Proc. Amer. Math. Soc. 130 (2002), no. 3, 915-923, [arXiv:/9903177], [pdf]
    (with Sebastian Goette)
48. Parallel spinors and holonomy groups
    J. Math. Phys. 41, 2395-2402 (2000)], [arXiv:9903062], [pdf]
    (with Andrei Moroianu)
49. Spinors, Self-Duality and IP Algebraic Curvature Tensors
    Proceedings of the Symposium on Contemporary Mathematics
    18-20 December 1998, Belgrade, Serbia
    (with Peter Gilkey)
50. Eigenvalue estimates for the Dirac operator on quaternionic Kähler manifolds,
    Math. Z. 230, 4 (1999), 727--751, [pdf]
    (with Wolfram Kramer und Gregor Weingart)
51. The First Eigenvalue of the Dirac Operator on Quaternionic Kähler Manifolds,
    Comm. Math. Phys. 199 (1998), 327-349, [arXiv:9709014], [pdf]
    (with Wolfram Kramer und Gregor Weingart)
52. Quaternionic Killing spinors,
    Ann. Glob. Anal. Geom. 16 (1998), 63-87., [pdf]
    (with Wolfram Kramer und Gregor Weingart)
53. A short proof of eigenvalue estimates for the Dirac operator on Riemannian and Kähler manifolds,
    Differential Geom. Appl., proceedings, Brno (1998), 137-140
54. Killing spinors are Killing vector fields in Riemannian Supergeometry,
    J. Geom. Phys. 26 (1998), no. 1-2, 37--50,  [pdf]
    (with D.V. Alekseevsky, V. Cortes und C. Devchand)
55. On nearly parallel G₂-structures
    J. Geom. Phys. 23, 259-286 (1997), [hal-00126037], [pdf]
    (Thomas Friedrich, Ines Kath und Andrei Moroianu)
56. Kählerian Killing spinors, complex contact structures and twistor spaces
    C. R. Acad. Sci. I Math. 323, 57-61 (1996), [pdf]
    (with Andrei Moroianu)
57. Complex Contact Structures and the First Eigenvalue of the Dirac Operator on Kähler Manifolds,
    Geom. and Funct. Analysis 5 (1995), 604-618]
    (with Klaus-Dieter Kirchberg)
58. Kählersche Killingspinoren und komplexe Kontaktstrukturen
    thesis, Humboldt Universität zu Berlin (1995)
59. The Spectrum of the Dirac Operator on Complex Projective Spaces,
    SFB 288 preprint, no. 95, Berlin (1993)
    (with Sönke Seifarth)

• Lecture: Geometrie für das Lehramt
• Seminar: Riemannsche Geometrie 1
• Seminar Geometry and Topology

SPP 2026 "Geometry at infinity!"

In the priority programme of the DFG SSP 2026 Prof. Uwe Semmelmann coordinates the projekt 15 "Spaces and Moduli Spaces of Riemannian Metrics with Curvature Bounds on compact and non-compact Manifolds".

The project concentrates on three major issues:

• The space of positive scalar curvature metrics
• Fiber bundles with geometric structures and spaces of Riemannian metrics
• Moduli spaces for nonnegative sectional and positive Ricci curvature

DFG-Project SE933/5-1: "Rigidity, stability and deformations in nearly parallel
G2-geometry"

Winter Term 2023/2024:

• Lecture Differentialgeometrie

Summer Term 2023:

• Lecture Topologie
• Seminar Der Laplace Operator

Winter Term 2022/2023:

• Lecture HM3
• Seminar Differentialgeometrie 

Sommer Term 2022:

• Lecture Riemannsche Geometrie
• Seminar  Einstein Metriken

Winter Term 2021/2022:

• Lecture Differentialgeometrie
• Seminar "Zahlen"

Sommer Term 2021:

• Lecture Geometrie für das Lehramt
• Lecture Topology

Summer Term 2020:

• Lecture Spin-Geometrie und Dirac-Operatoren
• Seminar Riemannsche Geometrie und Holonomie-Theorie

Winter Term 2019/2020

• Lecture Kähler Mannigfaltigkeiten
• Seminar Kalibrierte Geometrien

Summer Term 2019

• Vorlesung Differentialoperatoren auf Mannigfaltigkeiten
• Oberseminar Geometrie und Topologie

Winter Term 2018/2019

• Lecture HM 3
• Seminar: De Rham-Kohomologie
• Seminar of the Institute

Summer Term 2018

• Lecture Geometrie 
• Seminar: Der Laplace-Operator auf Riemannschen Mannigfaltigkeiten
• Seminar: Zahlen 
• Seminar of the Insitute

Winter Term 2017/18

• Lecture Topologie 
• Seminar Zahlen WiSe 17/18
• Seminar of the Insitute

Summer Term 2017

• Lecture Geometrie 
• Lecture Komplexe Geometrie A: Kähler Mannigfaltigkeiten
• Seminar of the Insitute

Winter Term 2016/17

• Lecture Differential-Geometrie
• LectureIndex-Theorie 1 (Spingeometrie und Diracoperatoren)
• Seminar of the Insitute

Winter Term 2015/17

• Lecture Topologie
• Seminar of the Insitute

Summer Term 2015

• Lineare Algebra II (Skript und Glossar)
• Seminar of the Insitute

Winter Term 2014/15

• Lineare Algebra I
• Seminar of the Insitute

Summer Term 2014

• Spingeometrie und Diracoperatoren
• Seminar of the Insitute

Winter Term 2013/2014

• Lecture Differentialoperatoren auf Mannigfaltigkeiten
• Seminar: Spin-Geometrie und Dirac-Operatoren
• Seminar of the Insitute

Winter Term 2012/2013

• Lecture Differential-Geometrie
• Seminar: Lie-Gruppen und Darstellungstheorie

Summer Term 2012

• Lecture Geometrie 
• Proseminar: Gruppen und Symmetrien
• Seminar: Hyperbolische Geometrie 

Summer Term 2011

• Lecture Riemannsche Geometrie
• Seminar-Zahlen

Winter Term 2010/2011

• Lecture Differentialgeometrie

Homepage at the University of  Köln (until 2010)

Bachelortheses

• Theorem von Seifert und van Kampen (2022)
• Variationsrechnung in der Riemannschen Geometrie (2022)
• Theorem of Seifert and van Kampen (2022)
• Context and curvature in homogeneous spaces (2020)
• Geometrically Formal Manifolds (2020)
• Curvature of symmetrc spaces (21020)
• Das Theorem von Obata (2019)
• Die Hopf-Invariante (2019)
• Die exzeptionelle Lie-Gruppe G2 (2018)
  
• Die Hitchin-Thorpe-Ungleichung auf vierdimensionalen Einstein-Mannigfaltigkeiten (2018)
• Orientierung von Mannigfaltigkeiten (2017)
• Kähler-Geometrie von Flaggenmannigfaltigkeiten (2017)
• Äquivalenzen 2-Punkt-homogener Räume (2015)
• Minimalflächen(2014)
• Geometrie der Hopf-Faserung (2014)
• Einstein-Metriken auf Riemannschen Submersionen (2013)
• Die Nearly Kähler Struktur der S6 (2013)

Mastertheses

• Homologie und Abbildungsgrad  (2024)
• Einstein deformations on homogeneous spaces (2020)
• Die Eguchi-Hanson Metrik (2019)

Diploma

• On the Lichnerowicz Laplace operator and its application to stability of spacetimes (2013)
• Die Sasaki-Metrik auf dem Tangential- und dem Sphärenbündel (2011)
• Lifting SU(3)-structures to nearly parallel G2-structures
• Intrinsische Torsion und Ricci-Krümung von SU(3)-Strukturen (2006)
• Das Spektrum des Diracoperators auf der Moufang-Ebene OP2 (2004)

Staatsexamen

• Gruppen-Beispiele, Eigenschaften und Anwendungen (2020)
• Gitter und ihre Anwendungen (2020)
• Der Fundamentalsatz der Algebra (2019)
• Ein Einblick in die Welt der tranzendierenden Zahlen (2019)
• Divisionsalgebren und Vektorkreuzprodukte (2019)
• Graphentheorie in der Schule (2018)
• Geometirsche Axiomatik am Beispiel von affiner und hyperbolischer Geometrie (2014)
• Theorie der Enveloppen und Anwendungen (2014)
• Minimalflächen (2008)
   

Doctoral Degree

• Paul Schwahn: Stability of Einstein Metrics on Homogeneous Spaces (2023)
• Konstantin Heil:Killing and Conformal Killing Tensors (2017)
• Sebastian Stock: Evolution of Geometries with Torsion (2010)
• Christian Stromenger: Sasakian Manifolds: Differential Forms, Curvature and Conformal Killing Forms (2010)
• Mihaela Pilca: Generalized Gradients of G-Structures and Kählerian Twistor Spinors (2009)

• Bogdan Alexandrov (1)
• Dmitri Alekseevsky(1)
• Florin Belgun (2)
• Vicente Cortes(1)
• Chand Devchand (1)
• Thomas Friedrich (1)
• Paul Gauduchon(1)
• Peter Gilkey (1)
• Nicolas Ginoux (1)
• Sebastian Goette(3)
• Tillmann Jentsch (1)
• Ines Kath (1)
• Klaus-Dieter Kirchberg (1)
• Wolfram Kramer (3)
• Andrei Moroianu (18)
• Paul-Andi Nagy (2)
• Mihaela Pilca 1)
• Sönke Seifarth (1)
• Gregor Weingart 6