Hostname: page-component-cb9f654ff-nr592 Total loading time: 0 Render date: 2025-08-23T17:43:36.732Z Has data issue: false hasContentIssue false

On G2-manifolds and geometry in dimensions 6 and 8

Published online by Cambridge University Press:  12 August 2025

Radu Pantilie*
Affiliation:
Institutul de Matematică “Simion Stoilow” al Academiei Române, 014700, Bucureşti, România
*
Corresponding author: Radu Pantilie; Email: r.pantilie@gmail.com

Abstract

We study the geometry induced on the local orbit spaces of Killing vector fields on (Riemannian) $G$-manifolds, with an emphasis on the cases $G=\textrm {Spin}(7)$ and $G=G_2$. Along the way, we classify the harmonic morphisms with one-dimensional fibres from $G_2$-manifolds to Einstein manifolds.

Information

Type
Research Article
Copyright
© The Author(s), 2025. Published by Cambridge University Press on behalf of Glasgow Mathematical Journal Trust

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Article purchase

Temporarily unavailable

References

Apostolov, V. and Salamon, S., Kähler reduction of metrics with holonomy $G_2$ , Comm. Math. Phys. 246 (2004), 4361.10.1007/s00220-003-1014-2CrossRefGoogle Scholar
Baird, P. and Wood, J. C., Harmonic morphisms between Riemannian manifolds, London Math. Soc. Monogr. (N.S.), Vol. 29, (Oxford Univ. Press, Oxford, 2003), xvi+520 pp.CrossRefGoogle Scholar
Besse, A. L., Einstein manifolds, Classics Math., (Springer-Verlag, Berlin, 2008), xii+516 pp.Google Scholar
Bryant, R. L., Metrics with exceptional holonomy, Ann. of Math. 126 (2) (1987), 525576.10.2307/1971360CrossRefGoogle Scholar
Cabrera, F. M., $SU(3)$ -structures on hypersurfaces of manifolds with $G_2$ -structure, Monatsh. Math. 148 (2006), 2950.10.1007/s00605-005-0343-yCrossRefGoogle Scholar
Chiossi, S. and Salamon, S., The intrinsic torsion of SU(3) and G2 structures, Differential geometry, Valencia, 2001, (World Scientific Publishing Co., Inc, River Edge, NJ, 2001), 115133.Google Scholar
Donaldson, S., Remarks on G2-manifolds with boundary, Surve. Differ. Geom, Vol. 22 (Int. Press, Somerville, MA, 2018), 103124, surveys in differential geometry 2017, celebrating the 50th anniversary of the journal of differential geometry.Google Scholar
Foscolo, L., Complete noncompact $Spin(7)$ -manifolds from self-dual Einstein 4-orbifolds, Geom. Topol. 25 (2021), 339408.CrossRefGoogle Scholar
Foscolo, L., Haskins, M. and Nordström, J., Complete noncompact $G_2$ -manifolds from asymptotically conical Calabi-Yau 3-folds, Duke Math. J. 170 (2021), 33233416.10.1215/00127094-2020-0092CrossRefGoogle Scholar
Fowdar, U., $S^1$ -quotient of $Spin(7)$ -structures, Ann. Global Anal. Geom. 57 (2020), 489517.CrossRefGoogle Scholar
Fowdar, U., $S^1$ -invariant Laplacian flow, J. Geom. Anal. 32 (2022), 27. no. 1, Paper No. 1710.1007/s12220-021-00784-0CrossRefGoogle Scholar
Fowdar, U., Spin(7) metrics from Kähler geometry, Comm. Anal. Geom. 31 (2023), 12171258.CrossRefGoogle Scholar
Madsen, T. B. and Swann, A., Multi-moment maps, Adv. Math. 229 (2012), 22872309.10.1016/j.aim.2012.01.002CrossRefGoogle Scholar
Pantilie, R., The penrose transform in quaternionic geometry, Ann. Univ. Ferrara Sez. VII Sci. Mat. 63 (2017), 169184.CrossRefGoogle Scholar
Pantilie, R., On the embeddings of the Riemann sphere with nonnegative normal bundles, Electron. Res. Announc. Math. Sci. 25 (2018), 8795.Google Scholar
Pantilie, R., Harmonic morphisms and the Penrose-Ward transform, Atti Accad. Naz. Lincei Rend. Lincei Mat. Appl. 30 (2019), 175194.Google Scholar
Pantilie, R., Twistor theory for exceptional holonomy, Mathematika 67 (2021), 5460.CrossRefGoogle Scholar
Pantilie, R. and Wood, J. C., Harmonic morphisms with one-dimensional fibres on Einstein manifolds, Trans. Amer. Math. Soc. 354 (2002), 42294243.10.1090/S0002-9947-02-03044-1CrossRefGoogle Scholar
Salamon, S., Riemannian geometry and holonomy groups, Pitman Research Notes in Mathematics Series, 201, (Longman Scientific & Technical, copublished in the United States with John Wiley & Sons, Inc., Harlow;-New York, 1989), viii+201.Google Scholar