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Keywords:
metric connection with torsion; intrinsic torsion; $G$-structure; characteristic connection; superstring theory; Strominger model; parallel spinor; non-integrable geometry; integrable geometry; Berger’s holonomy theorem; naturally reductive space; hyper-Kähler manifold with torsion; almost metric contact structure; $G_2$-manifold; $(7)$-manifold; $(3)$-structure; $3$-Sasakian manifold
Summary:
This review article intends to introduce the reader to non-integrable geometric structures on Riemannian manifolds and invariant metric connections with torsion, and to discuss recent aspects of mathematical physics—in particular superstring theory—where these naturally appear. Connections with skew-symmetric torsion are exhibited as one of the main tools to understand non-integrable geometries. To this aim a a series of key examples is presented and successively dealt with using the notions of intrinsic torsion and characteristic connection of a $G$-structure as unifying principles. The General Holonomy Principle bridges over to parallel objects, thus motivating the discussion of geometric stabilizers, with emphasis on spinors and differential forms. Several Weitzenböck formulas for Dirac operators associated with torsion connections enable us to discuss spinorial field equations, such as those governing the common sector of type II superstring theory. They also provide the link to Kostant’s cubic Dirac operator.
References:
[Ab84] E. Abbena: An example of an almost Kähler manifold which is not Kählerian. Bolletino U. M. I. (6) 3 A (1984), 383–392. MR 0769169 | Zbl 0559.53023
[AGS00] E. Abbena S. Gabiero S. Salamon: Almost Hermitian geometry on six dimensional nilmanifolds. Ann. Scuola Norm. Sup. Pisa Cl. Sci. (4) Vol. XXX (2001), 147–170. MR 1882028
[Agr02] I. Agricola: Connexions sur les espaces homogènes naturellement réductifs et leurs opérateurs de Dirac. C. R. Acad. Sci. Paris Sér. I 335 (2002), 43–46. MR 1920993 | Zbl 1010.53024
[Agr03] I. Agricola: Connections on naturally reductive spaces, their Dirac operator and homogeneous models in string theory. Comm. Math. Phys. 232 (2003), 535–563. MR 1952476 | Zbl 1032.53041
[ACF05] I. Agricola S. Chiossi A. Fino: Solvmanifolds with integrable and non-integrable $G_2$-structures. math.DG/0510300, to appear in Differential Geom. Appl. MR 2311729
[AF01] I. Agricola, Th. Friedrich: Global Analysis – Differential forms in Calculus, Geometry and Physics. Graduate Studies in Mathematics, Publications of the AMS 2002, Providence, Rhode Island 2002. MR 1998826
[AF03] I. Agricola, Th. Friedrich: Killing spinors in supergravity with $4$-fluxes. Classical Quantum Gravity 20 (2003), 4707–4717. MR 2019441 | Zbl 1045.83045
[AF04a] I. Agricola, Th. Friedrich: On the holonomy of connections with skew-symmetric torsion. Math. Ann. 328 (2004), 711–748. MR 2047649 | Zbl 1055.53031
[AF04b] I. Agricola, Th. Friedrich: The Casimir operator of a metric connection with totally skew-symmetric torsion. J. Geom. Phys. 50 (2004), 188–204. MR 2078225
[AF05] I. Agricola, Th. Friedrich: Geometric structures of vectorial type. math.DG/0509147, to appear in J. Geom. Phys. MR 2252869 | Zbl 1106.53033
[AFNP05] I. Agricola T. Friedrich P.-A. Nagy C. Puhle: On the Ricci tensor in the common sector of type II string theory. Classical Quantum Gravity 22 (2005), 2569–2577. MR 2153698
[AT04] I. Agricola, Chr. Thier: The geodesics of metric connections with vectorial torsion. Ann. Global Anal. Geom. 26 (2004), 321–332. MR 2103403 | Zbl 1130.53029
[Ale68] D. V. Alekseevski: Riemannian spaces with exceptional holonomy groups. Func. Anal. Prilozh. 2 (1968), 1–10. MR 0231313
[AMP98] D. V. Alekseevsky S. Marchiafava M. Pontecorvo: Compatible almost complex structures on quaternion Kähler manifolds. Ann. Global Anal. Geom. 16 (1998), 419–444. MR 1648844
[AC05] D. V. Alekseevsky V. Cortés: Classification of pseudo-Riemannian symmetric spaces of quaternionic Kähler type. Vinberg, Ernest (ed.), Lie groups and invariant theory. Providence, RI: American Mathematical Society 213 (AMS). Translations. Series 2. Adv. Math. Sci. 56 (2005), 33–62. MR 2140713
[AG86] V. Aleksiev G. Ganchev: On the classification of the almost contact metric manifolds. Mathematics and education in mathematics, Proc. 15th Spring Conf., Sunny Beach/Bulg. 1986, 155–161. MR 0872914
[Ale03] B. Alexandrov: $Sp(n)U(1)$-connections with parallel totally skew-symmetric torsion. J. Geom. Phys. 57 (2006), 323–337, math.DG/0311248. MR 2265474 | Zbl 1107.53012
[Ale04] B. Alexandrov: On weak holonomy. Math. Scand. 96 (2005), 169–189. MR 2153409 | Zbl 1079.53071
[AFS05] B. Alexandrov, Th. Friedrich N. Schoemann: Almost Hermitian $6$-manifolds revisited. J. Geom. Phys. 53 (2005), 1–30. MR 2102047
[AI00] B. Alexandrov S. Ivanov: Dirac operators on Hermitian spin surfaces. Ann. Global Anal. Geom. 18 (2000), 529–539. MR 1800590
[Ali01] T. Ali: $M$-theory on seven manifolds with $G$-fluxes. hep-th/0111220.
[AS53] W. Ambrose, I. M. Singer: A theorem on holonomy. Trans. Amer. Math. Soc. 75 (1953), 428–443. MR 0063739 | Zbl 0052.18002
[AS58] W. Ambrose, I. M. Singer: On homogeneous Riemannian manifolds. Duke Math. J. 25 (1958), 647–669. MR 0102842 | Zbl 0134.17802
[ADM01] V. Apostolov T. Drăghici A. Moroianu: A splitting theorem for Kähler manifolds whose Ricci tensors have constant eigenvalues. Internat. J. Math. 12 (2001), 769–789. MR 1850671
[AAD02] V. Apostolov J. Armstrong T. Drăghici: Local rigidity of certain classes of almost Kähler $4$-manifolds. Ann. Global Anal. Geom. 21 (2002), 151–176. MR 1894944
[Arm98] J. Armstrong: Almost Kähler geometry. Ph. D. Thesis, Oxford University, 1998.
[AS77] M. Atiyah, W. Schmid: A geometric construction for the discrete series for semisimple Lie groups. Invent. Math. 42 (1977), 1–62. MR 0463358
[AW01] M. Atiyah, E. Witten: $M$-theory dynamics on a manifold of $G_2$ holonomy. Adv. Theor. Math. Phys. 6 (2002), 1–106. MR 1992874 | Zbl 1033.81065
[Atr75] J. E. D’Atri: Geodesic spheres and symmetries in naturally reductive spaces. Michigan Math. J. 22 (1975), 71–76. MR 0372786
[AZ79] J. E. D’Atri, W. Ziller: Naturally reductive metrics and Einstein metrics on compact Lie groups. Mem. Amer. Math. Soc. 18 (1979). MR 0519928
[Bär93] Chr. Bär: Real Killing spinors and holonomy. Comm. Math. Phys. 154 (1993), 509–521. MR 1224089
[BS04] B. Banos A. F. Swann: Potentials for hyper-Kähler metrics with torsion. Classical Quantum Gravity 21 (2004), 3127–3135. MR 2072130
[BFGK91] H. Baum, Th. Friedrich R. Grunewald I. Kath: Twistors and Killing spinors on Riemannian manifolds. Teubner-Texte zur Mathematik, Band 124, Teubner-Verlag Stuttgart/Leipzig, 1991. MR 1164864
[BJ03] K. Behrndt C. Jeschek: Fluxes in $M$-theory on $7$-manifolds and $G$-structures. hep-th/0302047.
[Bel00] F. A. Belgun: On the metric structure of non-Kähler complex surfaces. Math. Ann. 317 (2000), 1–40. MR 1760667 | Zbl 0988.32017
[BM01] F. A. Belgun, A. Moroianu: Nearly Kähler $6$-manifolds with reduced holonomy. Ann. Global Anal. Geom. 19 (2001), 307–319. MR 1842572 | Zbl 0992.53037
[Ber55] M. Berger: Sur les groupes d’holonomie des variétés à connexion affine et des variétés riemanniennes. Bull. Soc. Math. France 83 (1955), 279–330. MR 0079806
[Ber61] M. Berger: Les variétés riemanniennes homogènes normales simplement connexes à courbure strictement positive. Ann. Sc. Norm. Sup. Pisa 15 (1961), 179–246. MR 0133083 | Zbl 0101.14201
[BTVh95] J. Berndt F. Tricerri L. Vanhecke: Generalized Heisenberg groups and Damek-Ricci harmonic spaces. LNM 1598, Springer, 1995. MR 1340192
[Bes87] A. Besse: Einstein manifolds. Ergebnisse der Mathematik und ihrer Grenzgebiete Bd. 10, Springer-Verlag Berlin-Heidelberg 1987. MR 0867684 | Zbl 0613.53001
[BDS01] A. Bilal J.-P. Derendinger, K. Sfetsos: Weak $G_2$-holonomy from self-duality, flux and supersymmetry. Nuclear Phys. B 628 (2002), 112–132. MR 1901225
[Bis89] J. M. Bismut: A local index theorem for non-Kählerian manifolds. Math. Ann. 284 (1989), 681–699. MR 1006380
[Bla76] D. E. Blair: Contact manifolds in Riemannian geometry. LNM 509 (1976), Springer. MR 0467588 | Zbl 0319.53026
[Bla02] D. E. Blair: Riemannian geometry of contact and symplectic manifolds. Progress in Mathematics vol. 203, Birkhäuser, 2002. MR 1874240 | Zbl 1011.53001
[BlVh87] D. E. Blair, L. Vanhecke: New characterization of $\varphi $-symmetric spaces. Kodai Math. J. 10 (1987), 102–107. MR 0879387
[Bob06] M. Bobieński: The topological obstructions to the existence of an irreducible $\mathrm{SO}(3)$-structure on a five manifold. math.DG/0601066.
[BN05] M. Bobieński, P. Nurowski: Irreducible $\mathrm{SO}(3)$-geometries in dimension five. to appear in J. Reine Angew. Math.; math.DG/0507152. MR 2338127
[Bon66] E. Bonan: Sur les variétés riemanniennes à groupe d’holonomie $G_2$ ou $\mathrm{Spin}(7)$. C. R. Acad. Sc. Paris 262 (1966), 127–129. MR 0196668
[BG99] C. P. Boyer, K. Galicki: $3$-Sasakian manifolds. in Essays on Einstein manifolds, (ed. by C. LeBrun and M. Wang), International Press 1999. MR 1798609 | Zbl 1008.53047
[BG01] C. P. Boyer, K. Galicki: Einstein manifolds and contact geometry. Proc. Amer. Math. Soc. 129 (2001), 2419–2430. MR 1823927 | Zbl 0981.53027
[BG07] C. P. Boyer, K. Galicki: Sasakian Geometry. Oxford Mathematical Monographs, Oxford University Press, to appear 2007. MR 2382957 | Zbl 1155.53002
[BGM94] C. P. Boyer K. Galicki B. M. Mann: The geometry and topology of $3$-Sasakian manifolds. J. Reine Angew. Math. 455 (1994), 183–220. MR 1293878
[BRX02] L. Brink P. Ramond, X. Xiong: Supersymmetry and Euler multiplets. hep-th/0207253.
[BG72] R. B. Brown, A. Gray: Riemannian manifolds with holonomy group $\mathrm{Spin}(7)$. Differential Geometry in honor of K. Yano, Kinokiniya, Tokyo, 1972, 41–59. MR 0328817
[Br87] R. L. Bryant: Metrics with exceptional holonomy. Ann. of Math. 126 (1987), 525–576. MR 0916718 | Zbl 0637.53042
[Br96] R. L. Bryant: Classical, exceptional, and exotic holonomies: a status report. Actes de la Table ronde de Géométrie Différentielle en l’honneur de M. Berger. Collection SMF Séminaires et Congrès 1 (1996), 93–166. MR 1427757 | Zbl 0882.53014
[Br03] R. L. Bryant: Some remarks on $G_2$-structures. in Proceeding of the 2004 Gokova Conference on Geometry and Topology (May, 2003), math.DG/0305124. Zbl 1115.53018
[BrS89] R. L. Bryant, and S. M. Salamon: On the construction of some complete metrics with exceptional holonomy. Duke Math. J. 58 (1989), 829–850. MR 1016448
[Bu04] J. Bureš: Multisymplectic structures of degree three of product type on $6$-dimensional manifolds. Suppl. Rend. Circ. Mat. Palermo II, Ser. bf 72 (2004), 91–98. MR 2069397
[BV03] J. Bureš, J. Vanžura: Multisymplectic forms of degree three in dimension seven. Suppl. Rend. Circ. Mat. Palermo II, Ser. 71 (2003), 73–91. MR 1982435
[Bu05] J. B. Butruille: Classification des variétés approximativement kähleriennes homogènes. Ann. Global Anal. Geom. 27 (2005), 201–225. MR 2158165
[CP99] D. M. J. Calderbank, H. Pedersen: Einstein-Weyl geometry. Surveys in differential geometry: Essays on Einstein manifolds. Lectures on geometry and topology, J. Diff. Geom. Suppl. 6 (1999), 387–423. MR 1798617 | Zbl 0996.53030
[Car22] E. Cartan: Sur une généralisation de la notion de courbure de Riemann et les espaces à torsion. C. R. Ac. Sc. 174 (1922), 593–595.
[Car23] E. Cartan: Sur les variétés à connexion affine et la théorie de la relativité généralisée (première partie). Ann. Ec. Norm. Sup. 40 (1923), 325–412, part one. MR 1509253
[Car24a] E. Cartan: Sur les variétés à connexion affine et la théorie de la relativité généralisée (première partie, suite). Ann. Ec. Norm. Sup. 41 (1924), 1–25, part one (continuation). MR 1509255
[Car24b] E. Cartan: Les récentes généralisations de la notion d’espace. Bull. Sc. Math. 48 (1924), 294–320.
[Car25] E. Cartan: Sur les variétés à connexion affine et la théorie de la relativité généralisée (deuxième partie). Ann. Ec. Norm. Sup. 42 (1925), 17–88, part two. English transl. of both parts by A. Magnon and A. Ashtekar, On manifolds with an affine connection and the theory of general relativity. Napoli: Bibliopolis (1986). MR 1509263
[Cha70] I. Chavel: A class of Riemannian homogeneous spaces. J. Differential Geom. 4 (1970), 13–20. MR 0270295 | Zbl 0197.18302
[ChG90] D. Chinea, G. Gonzales: A classification of almost contact metric manifolds. Ann. Mat. Pura Appl. 156 (1990), 15–36. MR 1080209
[ChM92] D. Chinea, J. C. Marrero: Classifications of almost contact metric structures. Rev. Roumaine Math. Pures Appl. 37 (1992), 581–599. MR 1172273
[ChF05] S. G. Chiossi A. Fino: Conformally parallel $G_2$-structures on a class of solvmanifolds. Math. Z. 252 (2006), 825–848. MR 2206629
[CS02] S. Chiossi, S. Salamon: The intrinsic torsion of $SU(3)$ and $G_2$ structures. in O. Gil-Medrano et. al. (eds.), Proc. Intern. Conf. Valencia, Spain, July 8-14, 2001, Singapore, World Scientific, 115–133 (2002). MR 1922042 | Zbl 1024.53018
[CI03] R. Cleyton, S. Ivanov: On the geometry of closed $G_2$-structures. math.DG/0306362. Zbl 1122.53026
[CI06a] R. Cleyton, S. Ivanov: Curvature decomposition of $G_2$ manifolds. to appear.
[CI06b] R. Cleyton, S. Ivanov: Conformal equivalence between certain geometries in dimension $6$ and $7$. math.DG/0607487.
[CS02] R. Cleyton, A. Swann: Cohomogeneity-one $G_{2}$-structures. J. Geom. Phys. 44 (2002), 202–220. MR 1969782 | Zbl 1025.53024
[CS04] R. Cleyton, A. Swann: Einstein metrics via intrinsic or parallel torsion. Math. Z. 247 (2004), 513–528. MR 2114426 | Zbl 1069.53041
[CKL01] G. Curio B. Körs, D. Lüst: Fluxes and branes in type II vacua and M-theory geometry with $G_2$ and $Spin(7)$ holonomy. hep-th/0111165.
[DI01] P. Dalakov, S. Ivanov: Harmonic spinors of Dirac operators of connections with torsion in dimension $4$. Classical Quantum Gravity 18 (2001), 253–265. MR 1807617
[dWNW85] B. de Witt H. Nicolai, N. P. Warner: The embedding of gauged $n=8$ supergravity into $d=11$ supergravity. Nuclear Phys. B 255 (1985), 29. MR 0792244
[dWSHD87] B. de Witt D. J. Smit, and N. D. Hari Dass: Residual supersymmetry of compactified $D=10$ Supergravity. Nuclear Phys. B 283 (1987), 165.
[Djo83] D. Ž. Djoković: Classification of trivectors of an eight-dimensional real vector space. Linear and Multilinear Algebra 13 (1983), 3–39. MR 0691457
[DF02] I. G. Dotti, A. Fino: HyperKähler torsion structures invariant by nilpotent Lie groups. Classical Quantum Gravity 19 (2002), 551–562. MR 1889760 | Zbl 1001.53031
[DO98] S. Dragomir L. Ornea: Locally conformal Kähler geometry. Progr. Math. vol. 155, Birkhäuser Verlag, 1998. MR 1481969
[Duf02] M. J. Duff: $M$-theory on manifolds of $G_2$-holonomy: the first twenty years. hep-th/0201062.
[Fer86] M. Fernández: A classification of Riemannian manifolds with structure group $\mathrm{Spin}(7)$. Ann. Mat. Pura Appl. 143 (1986), 101–122. MR 0859598
[Fer87] M. Fernández: An example of a compact calibrated manifold associated with the exceptional Lie group $G_2$. J. Differential Geom. 26 (1987), 367–370. MR 0906398
[FG82] M. Fernández, A. Gray: Riemannian manifolds with structure group $\mathrm{G}_2$. Ann. Mat. Pura Appl. 132 (1982), 19–45. MR 0696037
[FP02] J. Figueroa-O’Farrill G. Papadopoulos: Maximally supersymmetric solutions of ten- and eleven-dimensional supergravities. hep-th/0211089.
[Fin94] A. Fino: Almost contact homogeneous manifolds. Riv. Mat. Univ. Parma (5) 3 (1994), 321–332. MR 1342063 | Zbl 0847.53036
[Fin95] A. Fino: Almost contact homogeneous structures. Boll. Un. Mat. Ital. A 9 (1995), 299–311. MR 1336238 | Zbl 0835.53039
[Fin98] A. Fino: Intrinsic torsion and weak holonomy. Math. J. Toyama Univ. 21 (1998), 1–22. MR 1684209 | Zbl 0980.53060
[Fin05] A. Fino: Almost Kähler $4$-dimensional Lie groups with $J$-invariant Ricci tensor. Differential Geom. Appl. 23 (2005), 26-37. MR 2148908 | Zbl 1084.53025
[FG03] A. Fino, G. Grantcharov: Properties of manifolds with skew-symmetric torsion and special holonomy. Adv. Math. 189 (2004), 439–450. MR 2101226 | Zbl 1114.53043
[FPS04] A. Fino M. Parton S. Salamon: Families of strong KT structures in six dimensons. Comment. Math. Helv. 79 (2004), 317–340. MR 2059435
[Fri80] Th. Friedrich: Der erste Eigenwert des Dirac-Operators einer kompakten, Riemannschen Mannigfaltigkeit nichtnegativer Skalarkrümmung. Math. Nachr. 97 (1980), 117–146. MR 0600828 | Zbl 0462.53027
[Fri00] Th. Friedrich: Dirac operators in Riemannian geometry. Grad. Stud. Math. vol. 25, 2000. MR 1777332 | Zbl 0949.58032
[Fr01] Th. Friedrich: Weak $\mathrm{Spin}(9)$-structures on $16$-dimensional Riemannian manifolds. Asian Math. J. 5 (2001), 129–160. MR 1868168
[Fr03a] Th. Friedrich: $Spin(9)$-structures and connections with totally skew-symmetric torsion. J. Geom. Phys. 47 (2003), 197–206. MR 1991473 | Zbl 1039.53049
[Fri03b] Th. Friedrich: On types of non-integrable geometries. Rend. Circ. Mat. Palermo (2) Suppl. 71 (2003), 99–113. MR 1982437 | Zbl 1079.53041
[Fri06] Th. Friedrich: $G_2$-manifolds with parallel characteristic torsion. math.DG/0604441, to appear in Differential Geom. Appl. MR 2373939 | Zbl 1141.53019
[FG85] Th. Friedrich, R. Grunewald: On the first eigenvalue of the Dirac operator on $6$-dimensional manifolds. Ann. Global Anal. Geom. 3 (1985), 265–273. MR 0813132 | Zbl 0577.58034
[FI02] Th. Friedrich, S. Ivanov: Parallel spinors and connections with skew-symmetric torsion in string theory. Asian J. Math. 6 (2002), 303–336. MR 1928632 | Zbl 1127.53304
[FI03a] Th. Friedrich, S. Ivanov: Almost contact manifolds, connections with torsion and parallel spinors. J. Reine Angew. Math. 559 (2003), 217–236. MR 1989651 | Zbl 1035.53058
[FI03b] Th. Friedrich, S. Ivanov: Killing spinor equations in dimension $7$ and geometry of integrable $\mathrm{G}_2$-manifolds. J. Geom. Phys. 48 (2003), 1–11. MR 2006222
[FK89] Th. Friedrich, I. Kath: Einstein manifolds of dimension five with small eigenvalues of the Dirac operator. J. Differential Geom. 19 (1989), 263–279. MR 0982174
[FK90] Th. Friedrich, I. Kath: $7$-dimensional compact Riemannian manifolds with Killing spinors. Comm. Math. Phys. 133 (1990), 543–561. MR 1079795 | Zbl 0722.53038
[FKMS97] Th. Friedrich I. Kath A. Moroianu, U. Semmelmann: On nearly parallel $\mathrm{G}_2$-structures. J. Geom. Phys. 3 (1997), 256–286. MR 1484591
[FK00] Th. Friedrich, E. C. Kim: The Einstein-Dirac equation on Riemannian spin manifolds. J. Geom. Phys. 33 (2000), 128–172. MR 1738150 | Zbl 0961.53023
[FS79] Th. Friedrich, S. Sulanke: Ein Kriterium für die formale Selbstadjungiertheit des Dirac-Operators. Coll. Math. XL (1979), 239–247. MR 0547866 | Zbl 0426.58023
[FY05] J.-X. Fu, S.-T. Yau: Existence of supersymmetric Hermitian metrics with torsion on non-Kähler manifolds. hep-th/0509028.
[FP05] A. Fujiki, M. Pontecorvo: On Hermitian geometry of complex surfaces. in O. Kowalski et al. (ed.), Complex, contact and symmetric manifolds. In honor of L. Vanhecke. Selected lectures from the international conference “Curvature in Geometry" held in Lecce, Italy, June 11-14, 2003. Birkhäuser, Progr. Math. 234 (2005), 153–163. MR 2105147 | Zbl 1085.53065
[FI78] T. Fukami, S. Ishihara: Almost Hermitian structure on $S^6$. Hokkaido Math. J. 7 (1978), 206–213. MR 0509406
[GHR84] S. J. Gates C. M. Hull M. Rocek: Twisted multiplets and new supersymmetric nonlinear sigma models. Nuclear Phys. B 248 (1984), 157. MR 0776369
[GKMW01] J. Gauntlett N. Kim D. Martelli D. Waldram: Fivebranes wrapped on SLAG three-cycles and related geometry. hep-th/0110034.
[GMW03] J. P. Gauntlett D. Martelli, D. Waldram: Superstrings with intrinsic torsion. Phys. Rev. D (3) 69 (2004), 086002. MR 2095098
[Gau95] P. Gauduchon: Structures de Weyl-Einstein, espaces de twisteurs et variétés de type $S^1 \times S^3$. J. Reine Angew. Math. 469 (1995), 1–50. MR 1363825
[Gau97] P. Gauduchon: Hermitian connections and Dirac operators. Boll. Un. Mat. Ital. Ser. VII 2 (1997), 257–289. MR 1456265 | Zbl 0876.53015
[GT98] P. Gauduchon, K. P. Tod : Hyper-Hermitian metrics with symmetry. J. Geom. Phys. 25 (1998), 291–304. MR 1619847 | Zbl 0945.53042
[Gil75] P. B. Gilkey: The spectral geometry of a Riemannian manifold. J. Differential Geom. 10 (1975), 601–618. MR 0400315 | Zbl 0316.53035
[GLPS02] G. W. Gibbons H. Lü C. N. Pope, and K. S. Stelle: Supersymmetric domain walls from metrics of special holonomy. Nuclear Phys. B 623 (2002), 3–46. MR 1883449
[GKN00] M. Godlinski W. Kopczynski P. Nurowski: Locally Sasakian manifolds. Classical Quantum Gravity 17 (2000), L105–L115. MR 1791091
[Goe99] S. Goette: Equivariant $\eta $-invariants on homogeneous spaces. Math. Z. 232 (1999), 1–42. MR 1714278 | Zbl 0941.58016
[Gol69] S. I. Goldberg: Integrabilty of almost Kähler manifolds. Proc. Amer. Math. Soc. 21 (1969), 96–100. MR 0238238
[GP02] E. Goldstein S. Prokushkin: Geometric model for complex non-Kähler manifolds with $\mathrm{SU}(3)$-structure. Comm. Math. Phys. 251 (2004), 65–78. MR 2096734
[GZ84] C. Gordon, W. Ziller: Naturally reductive metrics of nonpositive Ricci curvature. Proc. Amer. Math. Soc. 91 (1984), 287–290. MR 0740188 | Zbl 0513.53049
[GP00] G. Grantcharov, Y. S. Poon: Geometry of hyper-Kähler connections with torsion. Comm. Math. Phys. 213 (2000), 19–37. MR 1782143 | Zbl 0993.53016
[Gra70] A. Gray: Nearly Kähler manifolds. J. Differential Geom. 4 (1970), 283–309. MR 0267502 | Zbl 0201.54401
[Gra71] A. Gray: Weak holonomy groups. Math. Z. 123 (1971), 290–300. MR 0293537 | Zbl 0222.53043
[Gra76] A. Gray: The structure of nearly Kähler manifolds. Math. Ann. 223 (1976), 233–248. MR 0417965 | Zbl 0345.53019
[GH80] A. Gray, L. M. Hervella: The sixteen classes of almost Hermitian manifolds and their linear invariants. Ann. Mat. Pura Appl. 123 (1980), 35–58. MR 0581924 | Zbl 0444.53032
[GSW87] M. B. Green J. H. Schwarz, and E. Witten: Superstring theory. Volume 2: Loop amplitudes, anomalies and phenomenology. Cambridge Monogr. Math. Phys. 1987. MR 0878144
[GKRS98] B. H. Gross B. Kostant P. Ramond, and S. Sternberg: The Weyl character formula, the half-spin representations, and equal rank subgroups. Proc. Natl. Acad. Sci. USA 95 (1998), no. 15, 8441–8442. MR 1639139
[Gru90] R. Grunewald: Six-dimensional Riemannian manifolds with a real Killing spinor. Ann. Glob. Anal. Geom. 8 (1990), 43–59. MR 1075238 | Zbl 0704.53050
[Gu35] G. B. Gurevich: Classification of trivectors of rank $8$. (in Russian), Dokl. Akad. Nauk SSSR 2 (1935), 353–355.
[Gu48] G. B. Gurevich: Algebra of trivectors II. (in Russian), Trudy Sem. Vektor. Tenzor. Anal. 6 (1948), 28–124. MR 0057861
[HHKN76] F. W. Hehl P. Von Der Heyde G. D. Kerlick J. M. Nester : General relativity with spin and torsion: Foundations and prospects. Rev. Modern Phys. 48 (1976), 393–416. MR 0439001
[HMMN95] F. W. Hehl J. D. McCrea E. W. Mielke Y. Ne’eman: Metric-affine gauge theory of gravity: field equations, Noether identities, world spinors, and breaking of dilation invariance. Phys. Rep. 258 (1995), 1–171. MR 1340371
[Hel78] S. Helgason: Differential Geometry, Lie Groups and Symmetric Spaces. Pure Appl. Math. vol. 80, Acad. Press, New York, 1978. MR 0514561 | Zbl 0451.53038
[Hit74] N. Hitchin: Harmonic spinors. Adv. Math. 14 (1974), 1–55. MR 0358873 | Zbl 0284.58016
[Hit00] N. Hitchin: The geometry of three-forms in six and seven dimensions. J. Differential Geom. 55 (2000), 547–576. MR 1863733
[Hit01] N. Hitchin: Stable forms and special metrics. math.DG/0107101; Contemp. Math. 288 (2001), 70–89. MR 1871001 | Zbl 1004.53034
[HP87] P. S. Howe, G. Papadopoulos: Ultraviolet behavior of two-dimensional supersymmetric nonlinear sigma models. Nuclear Phys. B 289 (1987), 264–276.
[HP92] P. S. Howe, G. Papadopoulos: Finitness and anomalies in $(4,0)$ supersymmetric sigma models. Nuclear Phys. B 381 (1992), 360.
[HP96] P. S. Howe, G. Papadopoulos: Twistor spaces for hyper-Kähler manifolds with torsion. Phys. Lett. B 379 (1996), 80–86. MR 1396267
[HP02] J.-S. Huang, P. Pandžić: Dirac cohomology, unitary representations and a proof of a conjecture of Vogan. J. Amer. Math. Soc. 15 (2002), 185–202. MR 1862801
[Hu86] C. M. Hull: Lectures On Nonlinear Sigma Models And Strings. PRINT-87-0480(Cambridge); Lectures given at Super Field Theories Workshop, Vancouver, Canada, July 25-Aug 6, 1986. MR 1102925
[Igu70] J.-I. Igusa,: A classification of spinors up to dimension twelve. Amer. J. Math. 92 (1970), 997–1028. MR 0277558 | Zbl 0217.36203
[Ike75] A. Ikeda: Formally self adjointness for the Dirac operator on homogeneous spaces. Osaka J. Math. 12 (1975), 173–185. MR 0376962 | Zbl 0317.58019
[In62] L. Infeld (volume dedicated to): Recent developments in General Relativity. Oxford, Pergamon Press & Warszawa, PWN, 1962. MR 0164694
[Iv04] S. Ivanov: Connections with torsion, parallel spinors and geometry of $\mathrm{Spin}(7)$-manifolds. Math. Res. Lett. 11 (2004), 171–186. MR 2067465
[IM04] S. Ivanov, I. Minchev: Quaternionic Kähler and hyperKähler manifolds with torsion and twistor spaces. J. Reine Angew. Math. 567 (2004), 215–233. MR 2038309
[IP01] S. Ivanov, G. Papadopoulos: Vanishing theorems and string background. Classical Quantum Gravity 18 (2001), 1089–1110. MR 1822270
[IPP05] S. Ivanov M. Parton, P. Piccinni: Locally conformal parallel $G_2$- and $\mathrm{Spin}(7)$-structures. math.DG/0509038, to appear in Math. Res. Lett. 13 (2006). MR 2231110
[Jel96] W. Jelonek: Some simple examples of almost Kähler non-Kähler structures. Math. Ann. 305 (1996), 639–649. MR 1399708 | Zbl 0858.53027
[Jen75] G. Jensen: Imbeddings of Stiefel manifolds into Grassmannians. Duke Math. J. 42 (1975), 397–407. MR 0375164 | Zbl 0335.53042
[Joy92] D. Joyce: Compact hypercomplex and quaternionic manifolds. J. Differential Geom. 35 (1992), 743–761. MR 1163458 | Zbl 0735.53050
[Joy96a] D. Joyce: Compact Riemannian $7$-manifolds with holonomy $G_2$. I. J. Differential Geom. 43 (1996), 291–328. MR 1424428
[Joy96b] D. Joyce: Compact Riemannian $7$-manifolds with holonomy $G_2$. II. J. Differential Geom. 43 (1996), 329–375. MR 1424428
[Joy96c] D. Joyce: Compact $8$-manifolds with holonomy $\mathrm{Spin}(7)$. Invent. Math. 123 (1996), 507–552. MR 1383960
[Joy00] D. Joyce: Compact manifolds with special holonomy. Oxford Science Publ., 2000. MR 1787733 | Zbl 1027.53052
[Kap83] A. Kaplan: On the geometry of groups of Heisenberg type. Bull. London Math. Soc. 15 (1983), 35–42. MR 0686346 | Zbl 0521.53048
[Ka71] T. Kashiwada: A note on a Riemannian space with Sasakian $3$-structure. Natur. Sci. Rep. Ochanomizu Univ. 22 (1971), 1–2. MR 0303449 | Zbl 0228.53033
[Ka01] T. Kashiwada: On a contact 3-structure. Math. Z. 238 (2001), 829–832. MR 1872576 | Zbl 1004.53058
[KS01] G. Ketsetzis, S. Salamon: Complex structures on the Iwasawa manifold. Adv. Geom. 4 (2004), 165–179. MR 2055676 | Zbl 1059.22012
[Kib61] T. W. B. Kibble: Lorentz invariance and the gravitational field. J. Math. Phys. 2 (1961), 212–221. MR 0127952 | Zbl 0095.22903
[Kl72] F. Klein: Das Erlanger Programm. Ostwalds Klassiker der exakten Wissenschaften Band 253, Verlag H. Deutsch, Frankfurt a. M., 1995. Zbl 0833.01037
[Kir86] K.-D. Kirchberg: An estimation for the first eigenvalue of the Dirac operator on closed Kähler manifolds of positive scalar curvature. Ann. Global Anal. Geom. 4 (1986), 291–325. MR 0910548 | Zbl 0629.53058
[Kir93] K.-D. Kirchberg: Killing spinors on Kähler manifolds. Ann. Global Anal. Geom. 11 (1993), 141–164. MR 1225435 | Zbl 0810.53033
[Kir05] K.-D. Kirchberg: Integrability conditions for almost Hermitian and almost Kähler $4$-manifolds. math.DG/0605611.
[Kir77] V. F. Kirichenko: $K$-spaces of maximal rank. Mat. Zametki 22 (1977), 465–476. MR 0474103
[KR02] V. F. Kirichenko A. R. Rustanov: Differential geometry of quasi-Sasakian manifolds. Sb. Math. 193 (2002), 1173-1201; translation from Mat. Sb. 193 (2002), 71–100. MR 1934545
[KN63] S. Kobayashi, K. Nomizu: Foundations of differential geometry I. Wiley Classics Library, Wiley Inc., Princeton, 1963, 1991. Zbl 0119.37502
[KN69] S. Kobayashi, K. Nomizu: Foundations of differential geometry II. Wiley Classics Library, Wiley Inc., Princeton, 1969, 1996.
[Kop73] W. Kopczyński: An anisotropic universe with torsion. Phys. Lett. A 43 (1973), 63–64.
[Kos56] B. Kostant: On differential geometry and homogeneous spaces II. Proc. N. A. S. 42 (1956), 354–357. MR 0088017 | Zbl 0075.31603
[Kos99] B. Kostant: A cubic Dirac operator and the emergence of Euler number multiplets of representations for equal rank subgroups. Duke Math. J. 100 (1999), 447–501. MR 1719734 | Zbl 0952.17005
[Kost02] B. Kostant: Dirac cohomology for the Cubic Dirac operator. in: Joseph, Anthony (ed.) et al., Studies in memory of Issai Schur. Basel: Birkhäuser. Progr. Math. 210 (2003), 69–93. MR 1985723 | Zbl 1165.17301
[KM01] B. Kostant, P. Michor: The generalized Cayley map from an algebraic group to its Lie algebra. preprint (arXiv:math.RT/0109066v1, 10 Sep 2001), to appear in The Orbit Method in Geometry and Physics (A. A. Kirillov Festschrift), Progr. Math. (2003). MR 1995382 | Zbl 1072.20051
[Kov03] A. Kovalev: Twisted connected sums and special Riemannian holonomy. J. Reine Angew. Math. 565 (2003), 125–160. MR 2024648 | Zbl 1043.53041
[KVh83] O. Kowalski, L. Vanhecke: Four-dimensional naturally reductive homogeneous spaces. Differential geometry on homogeneous spaces, Conf. Torino/Italy 1983, Rend. Sem. Mat., Torino, Fasc. Spec. (1983), 223-232. MR 0829007 | Zbl 0631.53039
[KVh84] O. Kowalski, L. Vanhecke: A generalization of a theorem on naturally reductive homogeneous spaces. Proc. Amer. Math. Soc. 91 (1984), 433–435. MR 0744644 | Zbl 0542.53029
[KVh85] O. Kowalski, L. Vanhecke: Classification of five-dimensional naturally reductive spaces. Math. Proc. Cambridge Philos. Soc. 97 (1985), 445–463. MR 0778679 | Zbl 0555.53024
[KW87] O. Kowalski, S. Wegrzynowski: A classification of $5$-dimensional $\varphi $-symmetric spaces. Tensor, N. S. 46 (1987), 379–386.
[Kre91] E. Kreyszig: Differential geometry. Dover Publ., inc., New York, 1991, unabridged republication of the 1963 printing. MR 1118149
[Lan00] G. Landweber: Harmonic spinors on homogeneous spaces. Represent. Theory 4 (2000), 466–473. MR 1780719 | Zbl 0972.22008
[LY05] J.-L. Li, S.-T. Yau: Existence of supersymmetric string theory with torsion. J. Differential Geom. 70 (2005), 143–182 and hep-th/0411136. MR 2192064 | Zbl 1102.53052
[Li63] A. Lichnerowicz: Spineurs harmoniques. C. R. Acad. Sci. Paris 257 (1963), 7–9. MR 0156292 | Zbl 0136.18401
[Li87] A. Lichnerowicz: Spin manifolds, Killing spinors and universality of the Hijazi inequality. Lett. Math. Phys. 13 (1987), 331–344. MR 0895296 | Zbl 0624.53034
[Lich88] A. Lichnerowicz: Les spineurs-twisteurs sur une variété spinorielle compacte. C. R. Acad. Sci. Paris Sér. I Math. 306 (1988), 381–385. MR 0934624 | Zbl 0641.53014
[LT89] D. Lüst, S. Theisen: Lectures on String Theory. Springer-Verlag, 1989. MR 1028064
[MSY06] D. Martelli J. Sparks S.-T. Yau: Sasaki-Einstein Manifolds and Volume Minimisation. hep-th/0603021.
[MC05] F. Martín Cabrera: Special almost Hermitian geometry. J. Geom. Phys. 55 (2005), 450–470. MR 2162420
[CMS96] F. Martín Cabrera M. D. Monar Hernandez A. F. Swann: Classification of $G_2$-structures. J. London Math. Soc. II. Ser. 53 (1996), 407–416. MR 1373070
[MCS04] F. Martín Cabrera, A. F. Swann: Almost Hermitian structures and quaternionic geometries. Differential Geom. Appl. 21 (2004), 199–214. MR 2073825
[McKW89] Y. McKenzie Wang: Parallel spinors and parallel forms. Ann. Global Anal. Geom. 7 (1989), 59–68. MR 1029845
[MZ04] S. Mehdi, R. Zierau: Principal Series Representations and Harmonic Spinors. to appear in Adv. Math. (preprint at http://www.math.okstate.edu/~zierau/papers.html) MR 2186917 | Zbl 1085.22011
[MS00] J. Michelson A. Strominger: The geometry of (super) conformal quantum mechanics. Comm. Math. Phys. 213 (2000), 1–17. MR 1782142
[Miq82] V. Miquel: The volume of small geodesic balls for a metric connection. Compositio Math. 46 (1982), 121–132. MR 0660156
[Miq01] V. Miquel: Volumes of geodesic balls and spheres associated to a metric connection with torsion. Contemp. Math. 288 (2001), 119–128. MR 1871004 | Zbl 1005.53012
[Na95] S. Nagai: Naturally reductive Riemannian homogeneous structure on a homogeneous real hypersurface in a complex space form. Boll. Un. Mat. Ital. A (7) 9 (1995), 391–400. MR 1336245 | Zbl 0835.53068
[Na96] S. Nagai: Naturally reductive Riemannian homogeneous structures on some classes of generic submanifolds in complex space forms. Geom. Dedicata 62 (1996), 253–268. MR 1406440 | Zbl 0860.53032
[Na97] S. Nagai: The classification of naturally reductive homogeneous real hypersurfaces in complex projective space. Arch. Math. 69 (1997), 523–528. MR 1480520 | Zbl 0901.53037
[Na02a] P.-A. Nagy: Nearly Kähler geometry and Riemannian foliations. Asian J. Math. 6 (2002) 481–504. MR 1946344 | Zbl 1041.53021
[Na02b] P.-A. Nagy: On nearly-Kähler geometry. Ann. Global Anal. Geom. 22 (2002), 167–178. MR 1923275 | Zbl 1020.53030
[NP97] P. Nurowski M. Przanowski: A four-dimensional example of Ricci-flat metric admitting almost-Kähler non-Kähler structure. ESI preprint 477, 1997; Classical Quantum Gravity 16 (1999), L9–L16. MR 1682582
[Nu06] P. Nurowski: Distinguished dimensions for special Riemannian geometries. math.DG/0601020.
[Par72] R. Parthasarathy: Dirac operator and the discrete series. Ann. of Math. 96 (1972), 1–30. MR 0318398 | Zbl 0249.22004
[Pen83] R. Penrose: Spinors and torsion in general relativity. Found. of Phys. 13 (1983), 325-339. MR 0838841
[PS01] Y. S. Poon, A. F. Swann: Potential functions of HKT spaces. Classical Quantum Gravity 18 (2001), 4711–4714. MR 1894924 | Zbl 1007.53038
[PS03] Y. S. Poon, A. F. Swann: Superconformal symmetry and HyperKähler manifolds with torsion. Comm. Math. Phys. 241 (2003), 177–189. MR 2013757
[Pu06] Chr. Puhle: The Killing equation with higher order potentials. Ph. D. Thesis, Humboldt-Universität zu Berlin, 2006/07.
[Reich07] W. Reichel: Über trilineare alternierende Formen in sechs und sieben Veränderlichen und die durch sie definierten geometrischen Gebilde. Druck von B. G. Teubner in Leipzig 1907, Dissertation an der Universität Greifswald.
[Roc92] M. Rocek: Modified Calabi-Yau manifolds with torsion. in: Yau, Shing-Tung (ed.), Essays on mirror manifolds. Cambridge, MA: International Press. 1992, 480–488. MR 1191438 | Zbl 0859.53050
[RT03] M. L. Ruggiero, A. Tartaglia: Einstein–Cartan theory as a theory of defects in space-time. Amer. J. Phys. 71 (2003), 1303–1313. MR 2016766
[Sal89] S. Salamon: Riemannian geometry and holonomy groups. Pitman Res. Notes Math. Ser. 201, Jon Wiley & Sons, 1989. MR 1004008 | Zbl 0685.53001
[Sal01] S. Salamon: Complex structures on nilpotent Lie algebras. J. Pure Appl. Algebra 157 (2001), 311–333. MR 1812058
[Sal03] S. Salamon: A tour of exceptional geometry. Milan J. Math. 71 (2003), 59–94. MR 2120916 | Zbl 1055.53039
[Sek87] K. Sekigawa: On some compact Einstein almost Kähler manifolds. J. Math. Soc. Japan 39 (1987), 677–684. MR 0905633 | Zbl 0637.53053
[Sch06] N. Schoemann: Almost hermitian structures with parallel torsion. PhD thesis, Humboldt-Universität zu Berlin, 2006. MR 2360237 | Zbl 1137.53014
[Sch24] J. A. Schouten: Der Ricci-Kalkül. Grundlehren Math. Wiss. 10, Springer-Verlag Berlin, 1924. MR 0516659
[Sch31] J. A. Schouten: Klassifizierung der alternierenden Größen dritten Grades in $7$ Dimensionen. Rend. Circ. Mat. Palermo 55 (1931), 137–156.
[Schr32] E. Schrödinger: Diracsches Elektron im Schwerefeld I. Sitzungsberichte der Preussischen Akademie der Wissenschaften, Phys.-Math. Klasse 1932, Verlag der Akademie der Wissenschaften Berlin, 1932, 436–460.
[Sim62] J. Simons: On the transitivity of holonomy systems. Ann. of Math. 76 (1962), 213–234. MR 0148010 | Zbl 0106.15201
[Sle87a] S. Slebarski: The Dirac operator on homogeneous spaces and representations of reductive Lie groups I. Amer. J. Math. 109 (1987), 283–301. MR 0882424 | Zbl 0649.58031
[Sle87b] S. Slebarski: The Dirac operator on homogeneous spaces and representations of reductive Lie groups II. Amer. J. Math. 109 (1987), 499–520. MR 0892596 | Zbl 0669.22003
[SSTP88] P. Spindel A. Sevrin W. Troost, and A. van Proeyen: Extended supersymmetric $\sigma $-models on group manifolds. Nuclear Phys. B 308 (1988), 662–698. MR 0967938
[Ste99] S. Sternberg: Lie algebras. Lecture Notes in Math. 1999.
[Str86] A. Strominger: Superstrings with torsion. Nuclear Phys. B 274 (1986), 253–284. MR 0851702
[Str69] K. Strubecker: Differentialgeometrie. II: Theorie der Flächenmetrik. Sammlung Göschen, W. de Gruyter, Berlin, 1969. MR 0239514 | Zbl 0169.23501
[Sw89] A. F. Swann: Aspects symplectiques de la géométrie quaternionique. C. R. Acad. Sci. Paris, Sér. I 308 (1989), 225–228. MR 0986384 | Zbl 0661.53023
[Sw91] A. F. Swann: HyperKähler and quaternionic Kähler geometry. Math. Ann. 289 (1991), 421–450. MR 1096180 | Zbl 0711.53051
[Sw00] A. F. Swann: Weakening holonomy. ESI preprint No. 816 (2000); in S. Marchiafava et. al. (eds.), Proc. of the Second Meeting on Quaternionic Structures in Mathematics and Physics, Roma 6-10 September 1999, World Scientific, Singapore 2001, 405–415. MR 1848678
[Taf75] J. Tafel: A class of cosmological models with torsion and spin. Acta Phys. Polon. B 6 (1975), 537–554.
[Ta89] S. Tanno: Variational problems on contact Riemannian manifolds. Trans. Amer. Math. Soc. 314 (1989), 349–379. MR 1000553 | Zbl 0677.53043
[Thu76] W. Thurston: Some simple examples of symplectic manifolds. Proc. Amer. Math. Soc. 55 (1976), 467–468. MR 0402764 | Zbl 0324.53031
[Tra73a] A. Trautman: On the structure of the Einstein-Cartan equations. Sympos. Math. 12 (1973), 139–162. MR 0376097 | Zbl 0273.53021
[Tra73b] A. Trautman: Spin and torsion may avert gravitational singularities. Nature Phys. Sci. 242 (1973) 7.
[Tra99] A. Trautman: Gauge and optical aspects of gravitation. Classical Quantum Gravity 16 (1999), 157–175. MR 1728438 | Zbl 0948.83010
[TV83] F. Tricerri, L. Vanhecke: Homogeneous structures on Riemannian manifolds. London Math. Soc. Lecture Notes Series, vol. 83, Cambridge Univ. Press, Cambridge, 1983. MR 0712664 | Zbl 0509.53043
[TV84a] F. Tricerri, L. Vanhecke: Geodesic spheres and naturally reductive homogeneous spaces. Riv. Mat. Univ. Parma 10 (1984), 123–131. MR 0777319 | Zbl 0563.53040
[TV84b] F. Tricerri, L. Vanhecke: Naturally reductive homogeneous spaces and generalized Heisenberg groups. Compositio Math. 52 (1984), 389–408. MR 0756730 | Zbl 0551.53028
[Vai76] I. Vaisman: On locally conformal almost kähler manifolds. Israel J. Math. 24 (1976), 338–351. MR 0418003 | Zbl 0335.53055
[Vai79] I. Vaisman: Locally conformal Kähler manifolds with parallel Lee form. Rend. Math. Roma 12 (1979), 263–284. MR 0557668 | Zbl 0447.53032
[VanN81] P. Van Nieuwenhuizen: Supergravity. Phys. Rep. 68 (1981), 189–398. MR 0615178 | Zbl 0465.53041
[Van01] J. Vanžura: One kind of multisymplectic structures on $6$-manifolds. Proceedings of the Colloquium on Differential Geometry, Debrecen, 2000, 375–391 (2001). MR 1859316
[Ve02] M. Verbitsky: HyperKähler manifolds with torsion, supersymmetry and Hodge theory. Asian J. Math. 6 (2002), 679–712. MR 1958088
[VE88] A. B. Vinberg, A. G. Ehlahvili: Classification of trivectors of a $9$-dimensional space. Sel. Math. Sov. 7 (1988), 63–98. Translated from Tr. Semin. Vektorn. Tensorm. Anal. Prilozh. Geom. Mekh. Fiz. 18 (1978), 197–233. MR 0504529 | Zbl 0648.15021
[McKW89] M. Y. Wang: Parallel spinors and parallel forms. Ann. Global Anal. Geom. 7 (1989), 59–68. MR 1029845 | Zbl 0688.53007
[WZ85] M. Y. Wang, W. Ziller: On normal homogeneous Einstein manifolds. Ann. Sci. Éc. Norm. Sup., $4^{e}$ série 18 (1985), 563–633. MR 0839687 | Zbl 0598.53049
[We81] R. Westwick: Real trivectors of rank seven. Linear and Multilinear Algebra 10 (1981), 183–204. MR 0630147 | Zbl 0464.15001
[Wi04] F. Witt: Generalised $G_2$-manifolds. Comm. Math. Phys. 265 (2006), 275–303, math.DG/0411642. MR 2231673 | Zbl 1154.53014
[Wi06] F. Witt: Special metrics and Triality. math.DG/0602414.
[Wol74] J. A. Wolf: Partially harmonic spinors and representations of reductive Lie groups. J. Funct. Anal. 15 (1974), 117–154. MR 0393351 | Zbl 0279.22009
[Yau78] S.-T. Yau: On the Ricci curvature of a compact Kähler manifold and the complex Monge-Ampŕe equations. I. Comm. Pure Appl. Math. 31 (1978), 339–411. MR 0480350
[Zil77] W. Ziller: The Jacobi equation on naturally reductive compact Riemannian homogeneous spaces. Comment. Math. Helv. 52 (1977), 573–590. MR 0474145 | Zbl 0368.53033
[Zil82] W. Ziller: Homogeneous Einstein metrics on spheres and projective spaces. Math. Ann. 259 (1982), 351–358. MR 0661203 | Zbl 0469.53043
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